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Guinness brownies cut into squares with Guinness frosting

I asked readers about St. Patrick’s Day dessert recipe requests recently. The outpouring of “anything with Guinness” convinced me to pick up a 6 pack and begin recipe testing. My kitchen smelled like a brewery at 9am on a Tuesday morning, but the result was well worth my boozy wake up call.

Before you run away at the thought of beer brownies, let me explain. These Guinness brownies do NOT taste like beer. Guinness stout, with its roast coffee and caramelized flavors, is often paired with chocolate in baking. They’re a natural duo because Guinness not only intensifies chocolate, but adds a malty background.

A quick internet search for “Guinness brownies” will spew out a million results. Even still, I wanted to try my hand at this popular dessert because even though brownies seem pretty basic, it’s difficult to maintain a desirable texture when you begin adding all sorts of stuff. And I was ready for the challenge.

stack of 3 Guinness brownies

Guinness beer bottle

VIDEO TUTORIAL: HOW TO MAKE GUINNESS BROWNIES

LET’S TALK FLAVOR + TEXTURE

Dark chocolate comes to mind first. These Guinness brownies aren’t overly sweet, so you’ll find yourself grabbing another. (If it’s not the brownies that are addicting, it’s the frosting. More on that below!) If we’re talking texture, they’re very dense and very moist. In fact, they’re the moistest brownies I’ve ever baked… because they’re the only brownies I’ve ever baked with Guinness! Unlike my chewy fudgy homemade brownies, these Guinness brownies are not particularly chewy. They taste like fudge. A square of dark chocolate fudge.

HOW IT WORKS

To impart enough flavor into the brownies, we’d have to use a lot of beer. But adding liquid to brownies makes absolutely no sense. So let’s take what we learned from homemade strawberry cake and reduce the beer down on the stovetop first. The heat evaporates the liquid, but leaves the flavor. Little liquid, lots of flavor, won’t turn our brownies into cake. We also do this with champagne in mimosa cupcakes. And I do the same thing with my Guinness chocolate cupcakes, too!

This step is really easy and requires zero effort from you. Pour an entire 12 oz bottle of Guinness into a saucepan. (The whole bottle! Nothing to waste!) Leave it alone to simmer for 20ish minutes, until it’s reduced down to 2/3 cup. This is less than half the liquid we started with, but triple the flavor.

We’ll use 1/2 cup of reduced Guinness in the brownie batter and the remaining 2 and 1/2 Tablespoons in the frosting.

reduced Guinness in a glass measuring cup

The rest of the brownie ingredients are usual suspects. Butter, sugar, eggs, flour. Instead of cocoa powder, we’re using pure solid chocolate. Sometimes I use a combination of pure chocolate AND cocoa powder in homemade brownies, but I wanted to keep things really simple since we’re taking extra time to reduce beer on the stove.

Besides Guinness, you know what else intensifies chocolate’s flavor? Coffee. I add espresso powder to both the brownie batter and frosting on top. It’s optional, but if you really want a deep dark chocolate brownie, don’t leave the espresso powder out.

pouring brownie batter into baking pan

FROSTING

The brownies are great alone, but better with this frosting. Their decadent nature screams for something creamy! (That being said, eat one with a pint of Guinness in the other hand.)

This caramel colored frosting is an interesting flavor. Interesting in a good way! It’s mostly espresso flavored, though there are lingering notes of maple too. Not sure how it tastes like maple, but I suspect it’s the combination of reduced Guinness, vanilla, and confectioners’ sugar. Whatever the reason, it’s SO GOOD because it’s SO DIFFERENT.

Guinness brownies cut into squares with Guinness frosting

Guinness brownies cut into squares with Guinness frosting

You might also love my Baileys and coffee cupcakes and shamrock cookies too!

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Guinness brownies cut into squares with Guinness frosting

Guinness Brownies

  • Author: Sally
  • Prep Time: 45 minutes
  • Cook Time: 35 minutes
  • Total Time: 3 hours
  • Yield: 1620 brownies 1x
  • Category: Brownies
  • Method: Baking
  • Cuisine: American

Description

These Guinness brownies are made from reduced Guinness Stout. They’re fudgy, rich, and topped with espresso powder and Guinness infused frosting!


Ingredients

Scale
  • one 12-ounce bottle Guinness Extra Stout
  • 3/4 cup (12 Tbsp; 175g) unsalted butter
  • two 4-ounce bars (226g) semi-sweet chocolate, coarsely chopped*
  • 1 and 1/4 cups (250g) granulated sugar
  • 3 large eggs
  • 1 teaspoon pure vanilla extract
  • 1 cup (125g) all-purpose flour (spoon & leveled)
  • 1/2 teaspoon salt
  • optional: 1/2 teaspoon espresso powder

Guinness Frosting

  • 1/2 cup (1 stick; 115g) unsalted butter, softened to room temperature
  • 2 cups (240g) confectioners’ sugar
  • 23 Tablespoons reduced Guinness (from step 1)
  • 1 teaspoon espresso powder
  • 1/2 teaspoon pure vanilla extract
  • 1/4 teaspoon salt

Instructions

  1. In a small saucepan, bring the Guinness to a boil over medium-high heat. Once boiling, reduce to medium heat and allow to simmer until reduced down to 2/3 cup, about 20-22 minutes. Set aside to cool for at least 10 minutes. You will use 1/2 cup in the brownies and the rest in the frosting.
  2. Preheat the oven to 350°F (177°C) and grease a 9×9 inch pan or line with aluminum foil or parchment paper, leaving an overhang on the sides to lift the finished brownies out (makes cutting easier!). Set aside.
  3. Place the butter and chopped chocolate in a large microwave-safe bowl. Melt in 30 second increments, whisking after each, until completely smooth. Whisk in the sugar and 1/2 cup of reduced Guinness until completely combined. Whisk in the eggs and vanilla extract. Finally, whisk in the flour, salt, and espresso powder (if using). The batter will be thick and shiny. Pour/spread evenly into prepared pan.
  4. Bake for 32 minutes, then test the brownies with a toothpick. Insert it into the center of the pan. If it comes out with wet batter, the brownies are not done. If there are only a few moist crumbs, the brownies are done. Keep checking every 2 minutes until you have moist crumbs. My brownies take about 35 minutes.
  5. Remove from the oven and place on a wire rack to cool completely before frosting or cutting into squares.
  6. Make the frosting: In a large bowl using a handheld or stand mixer fitted with a whisk attachment, beat the butter on high speed until completely smooth and creamy, about 2-3 minutes. Add the confectioners’ sugar, beating on low at first then increasing to high speed. Once creamy and combined, beat in 2 Tablespoons of reduced Guinness, the espresso powder, vanilla extract, and salt. Taste. Add the remaining reduced Guinness if needed. If you want the frosting a little thinner, add a splash of milk.
  7. Frost cooled brownies.
  8. Cover and store leftover brownies at room temperature for up to 1 week.

Notes

  1. Make Ahead Instructions: Freeze frosted or unfrosted brownies up to 3 months. Thaw overnight in the refrigerator then bring to room temperature before serving.
  2. Special Tools: KitchenAid Hand Mixer | Glass Mixing Bowls | Saucepan | 9×9 Baking Pan | Icing Spatula
  3. Chocolate: You can find 4 ounce chocolate baking bars in the baking aisle. I like using Ghirardelli or Baker’s brand. You can use 8 ounces (heaping 1 and 1/3 cups) of quality chocolate chips instead, such as Ghirardelli brand.

Keywords: Guinness brownies

Reader Questions and Reviews

  1. Hey Sally these look amazing and would be great for St. Patrick’s day but I really only need a smaller amount because it just my family. Is there a way I could 1/2 the recipe for an 8 x 8? And would you suggest rounding up on the eggs?

    1. Hi Kate! You should be able to halve the recipe to bake it in a 9×4 loaf pan. They’ll be slightly thicker. Halving for an 8×8 pan would yield too thin brownies. Our general rule for halving an egg is to crack it open, beat the yolk and white together with a fork, measure the volume (should be a few Tbsp), then use half.

  2. These are delicious! Very subtle flavor on the Guinness. I don’t like espresso so didn’t use it, and they still were wonderful! To make it extra fun for St. Patty’s Day, I dyed the frosting green! Highly recommend adding that fun step.

      1. Hi Amber! You really want pure chocolate for this recipe, almond bark contains added oils.

    1. That frosting is maybe the best part of the the brownie!

  3. Hi,
    Is there a reason you used the Extra Stout Guinness? Does the original Guinness not work because of the Nitro?

      1. Hi M, If you use salted butter, you can use 1/2 of the recommended salt.

  4. Thanks Sally for this recipe. I made a batch last night for a little market I supply bake goods to a couple of time a week. This morning I got a call for another batch. I give you credit for the recipe and every recipe I try of yours turns out perfect. Love the step by step directions and videos! Thanks so much!!!!

  5. Hello! I love your recipes! I am making these for St. Patty’s Day! Would it work to melt the chocolate and butter in the hot Guinness rather than the microwave?

    1. Hi Sarah, we actually haven’t tested the recipe that exact way before but I’m sure it would be fine.

  6. Love this recipe! Can you reduce extra Guinness and store for later usage?

  7. This recipe for brownies is fenomenal. I was looking for something special for staying home St. Patricks Day.. and here it is.. Perfect dessert.
    Thank you so much for this idea!

  8. Hi. I don’t have espresso powder. Is there a substitute that can be used? Cocoa powder–or strong coffee in place of some of the liquid? I also plan to use Brooklyn Brewery Black Chocolate Stout–no Guinness on hand either!

    1. Hi Barb! If you have instant coffee you could use that instead, but it isn’t quite as strong as espresso powder. You can increase the amount or simply expect a milder flavor. If you don’t have either, you can simply leave it out. Let us know how they go for you!

  9. Hi Sally! This is me Laura, my husband is the baker in the house, a very good baker I may add….he made these Guinness brownies for our Irish dinner tonight. The flavor is so complex! A special brownie indeed. Made the frosting, tastes great as well….but his frosting looks a bite muddled, not smooth and shiny like your photo….what can we do to make it look as good as it tastes? Happy St Patrick’s Day! Laura

    1. Hi Laura! We’re so glad you enjoyed these brownies. For smooth frosting, first make sure to beat the butter until creamy before adding the rest of the ingredients. Second, sifting your confectioner’s sugar can prevent the frosting from being grainy. Hope this helps for next time!

      1. Fabulous complex flavor, wonderful for a special dessert, or St Patrick’s Day…..!

  10. Happy St Patrick’s Day 2021! I just made these and they are amazing!! I didn’t have a 9×9 pan so I used mini cupcake tins and baked at 350F on one rack for 15 minutes – it made 42 brownie bites. I also didn’t have espresso powder so I substituted Grind Espresso Shot Liqueur – swapped out half the vanilla in the batter; kept all vanilla in the frosting and added the liqueur by the half teaspoon until I got the flavor and consistency I wanted, about 2.5-3 tsp. WOW!!!!!

    1. I are these a fudge chewy texture or it more cake like? If not, how do u make them to that texture?

      1. They were fudgy in the middle and chewy/crunchy on the edges. Next time I plan to check at 13 minutes bc I want them less crunchy on the edges.

  11. OMG these are THE best brownies ever. I followed the recipe exactly. Definitely the only brownie recipe I’ll be using from now on!

  12. Our grocery store does not carry espresso powder, but has espresso instant coffee …could I substitute that with similar results?l

    1. Hi Amy! You can, yes, but instant coffee powder isn’t quite as strong as espresso powder. You can increase the amount or simply expect a milder flavor.

  13. If you are torn on whether or not to make these, DO IT! I was hesitant at first, I mean beer in my brownies? No way! But I was curious so I tried them out for Saint Patrick’s Day and I am telling you, they were so freakin delicious! The brownie had such a rich, complex flavor! And the frosting?! I’m not a fan of frosting on my brownies but I was curious about how it would taste so I made it anyways and served it on the side. Absolutely fantastic! I’m not sure how Sally does it but she is the Dumbledore of baking magic! If you are the least bit considering making these, I highly recommend you do!

  14. Just made them this week with a home brew irish stout and they were amazing! Worth trying.

  15. I made these for my co-workers for St. Patrick’s Day! Everyone absolutely loved them! I couldn’t find the Extra Stout, but the Stout worked just fine. I love the hint of coffee flavor with the espresso powder. The frosting is what really takes the brownie over the top!

  16. I just made these with some leftover Guinness from St. Patrick’s Day. The espresso mixed with the hint of Guinness is INSANE! The frosting made such a difference too. I never knew buttercream could taste so amazing!

  17. I made this yesterday.. They should be called Edible Devils..I couldn’t find a bottle of Guinness, only a can, so used that. Also I had on hand semi sweet allergen free chocolate chips and dark chocolate chunks. I added 1 cup of sugar instead of the extra 1/4 and only made half the recipe of frosting…Reduced Guilt? LOL.. I had one for breakfast with coffee and soon after found myself on the treadmill with loads of energy. I have given a few bars out and the reaction is : omg..

  18. AB. SO. LUTE. LY DELICIOUS!
    Best brownies I’ve ever made. My husband has just eaten 3 in a row and I’ve had to hide them. This is such a great recipe. The only need-based changes I made were:
    -Was out of vanilla so used bourbon instead in the batter. Why not?
    -Replaced the vanilla in the icing with an extra spoonful of the Guinness.
    -Icing was a bit too thick and I didn’t have milk, but I had kefir. I used that and I think the tang from the kefir added such a delicious taste to the icing that I will use it again next time. Maybe sour cream or greek yogurt or cream cheese would have a similar effect?

    So. So. SO. Good.

  19. Hi Sally!

    I tried this recipe and loved it! But my friends commented that they couldn’t really taste the Guinness flavour (well not as much as their expectation I guess). How would you recommend to improve on the Guinness flavour?

    1. Hi Baun, We are so glad you loved the recipe! Your friends are right, the brownies do not taste like beer. The Guinness role is to intensify the chocolate and add a malty background flavor. You will taste it more in the frosting if you try that!

      1. Thanks!

        Also, I once followed all your steps and this recipe, but I ended up with very liquid-batter and it turn out to be too thin (even though I use the 8×8 square pan). Any advise on where I messed up? Should I reduce butter or egg?

  20. Hello Sally, been following your recipes for a few weeks and all I can say is WHERE HAVE YOU BEEN ALL MY LIFE! Lol. I plan on making this recipe but I want to use coco powder in place of the chocolate bars. Is it possible to switch? If yes please let me know how. Thank you.

    1. Hi Pearl, we’re so glad you’re enjoying out recipes! Using cocoa powder in these brownies would require more recipe testing. Best to stick with the recipe as written for best results but let us know if you try anything!

  21. I’ve tried a lot of from-scratch brownies over the years, and to be honest never liked them as much as boxed brownie mixes. I decided to try these since Guinness is one of the only beers I like. Instead of the Guinness Extra Stout, I used a Guinness Nitro Cold Brew Coffee (beer with coffee). I kept the rest of the recipe exactly the same, even adding the espresso powder (although I didn’t make the frosting). And let me say… NEW FAVORITE BROWNIE!! I’m a little embarrassed to say that two of us ate half of the pan in less than 24 hours… but oh my they are DELICIOUS and totally worth it! Will 100% be making these again. Another amazing recipe, Sally!

    1. Absolutely! You can double this recipe for a 9×13 inch pan. We’re unsure of the exact bake time.

  22. these looked great and i was excited to make them, but i only own an 8×8 pan. i made these with your exact directions, but i ended up using guinness draft because that was all i had on hand. (also used a mixture of semisweet baking chips and leftover unsweetened baking chocolate, added a little sugar so that it all balanced out.)

    baked them for about 34 minutes since they were a little thicker, kept checking every two minutes like you instructed, and at 40 minutes i just decided to pull them from the oven, as i was nervous about overbaking them. they still seemed to need more time. was getting strange mixed readings when pricking the brownies with a cake tester – in some spots it came out covered in batter, and in other spots it came out almost clean. (the middle appeared to be the most baked, oddly – it was the sides that looked to need more time.)

    three whole hours of cooling time later, they were still slightly warm on the bottom – so i decided to cut and pull them from the pan to let them finish cooling that way, so i could make the frosting without waiting until tomorrow. to my horror, some brownies appeared to be perfectly cooked, some slightly undercooked and fudgy (but still edible) and a few had the consistency of mostly raw batter, falling apart in my hands!

    what did i do wrong exactly? i know that an 8×8 yields thicker brownies than a 9×9, but does this surface area difference really change the baking process THIS much? why did the brownies end up differing so much in the same pan? i’d be glad to try to make these again if i at least figure that out.

    1. Even though it’s only an inch smaller around all sides, that does make a big difference in baking– I really do recommend a 9-inch pan for these brownies. Smaller pan does mean thicker brownies as you know, but if the brownies are too thick, they may not ever bake properly without browning on top/around the edges. I’m not surprised the brownies needed longer time and if you try the recipe again in an 8-inch pan, tenting the pan with foil after about 20-25 minutes and extending the bake time will help. (Use a 9-inch square pan if you can though!)

  23. Made these last night for an Irish then night out family was doing, and they were delicious! Paired really well with a glass of Guinness too :). My frosting came out a little weird looking though. It was smooth at first but then maybe I mixed it for too long, and the texture ended up kind of grainy/bubbly looking. It still tasted great though!

  24. I love these brownies! I often use a local brew that is a chocolate peanut butter stout instead of Guinness. Is there a way to modify this recipe to make it in a 9×13 pan? My friends loke these so much, a 9×9 is sometimes not big enough for all of us

  25. Hi Sally. I’ve made these brownies a couple times now and the flavor is amazing! The first time my icing turned out perfectly but the last two times it seemed to almost separate? I’m not sure what I did differently. Could my butter be softened too much? Too much liquid? Other thoughts?

    1. Hi Christine, it’s likely the butter is too soft– make sure it’s still cool to the touch. And reducing the liquid would also help. Glad you love these!

  26. Hi I would like to know have you try to heat it up in the microwave before you serve?

    1. Hi Caryn! If you leave your brownies unfrosted you can certainly heat up each individual brownie for a few seconds (depending on your microwave strength) to warm before enjoying.

  27. These sound delicious and I plan to make them for a party this weekend! Is the frosting thick enough to put in piping bag an pipe a swirl?

    1. Hi Theresa, You should be able to make simple swirls. You can always add more confectioner’s sugar to thicken it up if needed for more intricate piping tips.

  28. This might be the best brownie I have ever tasted. The recipe was super easy. The brownie came out rich and fudgey and the coffee in the frosting is a perfect match. I will make this over and over.

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