Mega Peanut Butter Swirl Brownies

stack of 3 peanut butter swirl brownies

Can you believe I’ve never shared a peanut butter swirl brownie recipe on my blog before?

Actually, wait. I did share a *skinnier* version about 5 years ago that’s made with zero flour, a blender, Greek yogurt, and oats. Sounds very strange, but it totally works. By the way, I’ve since made them with coconut sugar and they’re SO GOOD.

peanut butter swirl brownies cut into squares

We’re not on a diet today. This is the real deal. The obnoxiously fudgy dense brownies completely overloaded with chocolate and swirled with an awesomely rich peanut butter filling and– wait for it– filled with chopped peanut butter cups. If you listen closely, you can hear your bikini running away in fright.

I label them “mega” because they’re one of the richest desserts to come out of my oven. The base of the brownies is this homemade brownie recipe, though I add a little more chocolate. If you’ve tried that brownie recipe before, you can imagine how “mega” the peanut butter swirl version is!

I made the first batch of mega peanut butter swirl brownies nearly a month ago when our friends came to visit. I knew neither Kevin nor I could be trusted with an entire batch just to ourselves and I’m going to warn you now– make sure you’ve got company coming over or a large group to help you snack on these! Self control seems to run for the hills. Maybe it’s hanging out with our bikinis.

So here’s how we’re going to make them…

brownie batter in a glass bowl with chopped peanut butter cups

Whip up the homemade brownie batter. That’s easy. Curious about the ingredients and why each is important? Here’s that post you can review.

Add chopped peanut butter cups. ♥

Prepare the epic PB swirl next. There’s a lot of it because we want mega peanut butter swirls in every single bite. Clearly, we’re not skimping on anything today.

Only 4 ingredients needed for the peanut butter swirl: creamy peanut butter, confectioners’ sugar, butter, and vanilla extract– pretty much the same ingredients we use for peanut butter balls, too. You’re using butter and vanilla in the brownie recipe anyway, so really it’s just 2 additional ingredients. The easiest way to combine them all is using a mixer.

peanut butter swirl mixture in a glass bowl with a hand mixer

How to Perfect the Swirl

Since we’re making a super mega dessert, we want to make sure it looks pretty darn good too. The swirling part is an art, but one you can easily master on the first try. All you do is randomly drop spoonfuls of brownie batter and spoonfuls of peanut butter batter into the lined brownie pan. It’s going to be super haphazard like so:

scoops of brownie batter and peanut butter swirl mixture in a baking pan lined with parchment paper

Save a couple spoonfuls of brownie batter to fill in any gaps or cover any heavy peanut butter sections. Then take a knife and run it up and down both horizontally and vertically, creating swirls of the two batters like so:

peanut butter mixture and brownie batter swirled together in a baking pan

Easy stuff, right? Sprinkle the pan with a couple leftover chopped peanut butter cups and pop into the oven.

This brownie recipe, without the peanut butter swirl, takes about 30-32 minutes. The peanut butter swirl adds a couple minutes to the bake time. But I urge you to watch the brownies themselves– not the clock. The bake time is simply a guideline and you shouldn’t be surprised or alarmed if the brownies take longer or shorter. You’ll know the brownies are done when the top looks set. Test them using a toothpick. If there is wet batter on the toothpick, the brownies need more time. If there are a few moist crumbs on the toothpick, the brownies are done. If the toothpick is clean, the brownies are overdone. So keep your eyes on these!

overhead image of peanut butter swirl brownies

How to Neatly Cut Brownies

Another art you can master on the first try!

  1. Wait until the brownies have completely cooled. What a buzzkill. But this helps ensure some neatly sliced fudgy brownies! I always stick the slightly cooled pan in the fridge for an hour or so to speed up the process.
  2. Use a plastic knife. One of those dinky ones you buy for potlucks and picnics. SO WEIRD, right? But a plastic knife strangely keeps layered or swirled brownies neat. It’s my little trick for neatly cut mint chocolate brownies. If you don’t have one and really don’t feel like getting one, just use a very sharp knife.
  3. Whichever knife you use, wipe it clean with a paper towel between each cut.

That’s all, folks!

peanut butter swirl brownie

My last piece of advice: have a mega glass of milk handy. Or at least some sweatpants.

Print
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peanut butter swirl brownie

Mega Peanut Butter Swirl Brownies

  • Author: Sally
  • Prep Time: 20 minutes
  • Cook Time: 35 minutes
  • Total Time: 3 hours, 20 minutes
  • Yield: 18-24 brownies
  • Category: Brownies
  • Method: Baking
  • Cuisine: American

Description

These mega peanut butter swirl brownies are unapologetically rich and fudgy! This homemade brownie recipe is one of my favorites and so easy to make.


Ingredients

  • 1 cup (16 Tbsp; 2 sticks; 230g) unsalted butter, divided
  • one 4 ounce (113g) semi-sweet chocolate bar, coarsely chopped*
  • 2 cups (400g) granulated sugar
  • 3 large eggs, at room temperature
  • 2 teaspoons pure vanilla extract, divided
  • 1 cup (82g) unsweetened natural or dutch-process cocoa powder*
  • 1 cup (125g) all-purpose flour (spoon & leveled)
  • 1 teaspoon salt
  • 1 and 1/2 cups chopped peanut butter cups
  • 1 cup (250g) creamy peanut butter*
  • 1/2 cup (60g) confectioners’ sugar

Instructions

  1. Preheat the oven to 350°F (177°C) and grease a 9×13 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.
  2. Brownie batter: In a microwave-safe bowl, combine 3/4 cup butter (12 Tbsp; 1 and 1/2 sticks) and chopped chocolate. Melt in 30 second increments, whisking after each, until completely smooth. Whisk in the granulated sugar until completely combined, then whisk in the eggs and 1 teaspoon vanilla. The batter will be light brown and a little dull looking.
  3. Add the cocoa powder, flour, and salt. Fold it all together with a rubber spatula or wooden spoon. Batter will be very thick. Stir in chopped peanut butter cups, reserving a small handful to sprinkle on top. Set aside.
  4. Peanut butter swirl: Melt the remaining butter. Using a hand-held or stand mixer fitted with a paddle or whisk attachment, beat the melted butter, remaining 1 teaspoon of vanilla, the peanut butter, and confectioners’ sugar until smooth. Drop big spoonfuls of most of the chocolate batter randomly into the prepared pan– see photo above for a visual. Top with random spoonfuls of all of the peanut butter batter. Drop random spoonfuls of remaining chocolate batter over any bare spots or heavy peanut butter spots. Using a knife, swirl the batters together. The brownie batter is pretty thick, so do your best. Sprinkle with any leftover peanut butter cups.
  5. (See note about how to tell if brownies are done in the post above.) Bake for 30 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 33-36 minutes.
  6. Remove from the oven and place on a wire rack to cool completely before cutting into squares. Cover and store leftover brownies at room temperature for up to 1 week.

Notes

  1. Make Ahead Instructions: Brownies freeze well up to 3 months. Thaw overnight in the refrigerator then bring to room temperature before serving.
  2. Chocolate Bars: Chocolate bars are typically sold in 4 ounce bars. I suggest Ghirardelli, Baker’s brand, or Lindt. Do not use chocolate chips.
  3. Cocoa Powder: You can use either natural or dutch-process cocoa powder. I prefer dutch-process for a smoother flavor.
  4. Peanut Butter:Use a generic creamy peanut butter like Jif or Skippy. Crunchy could work too. Do not use natural, homemade, or super oily brand as the swirl will not set up properly.

Here’s that older recipe for the skinny version!

stack of 2 peanut butter chocolate brownies

118 Comments

  1. Maja Harder says:

    I love the structure of this cake! It looks delicious 

  2. These look fantastic! I love the chocolate and peanut butter combo!
    I had a question about photos for someone starting out a food blog. Do you think it’s important to have a lot of pictures of the recipe in each post or is one fine? I’m not much of a photographer so any tips would be helpful. Thanks!

    1. I’d say start with whatever you are comfortable with. Photography wasn’t my focal point in the beginning, but has slowly become my passion. I didn’t post my photos in the beginning. But who knows, maybe you’ll love it someday!

  3. heather (delicious not gorgeous) says:

    those cutting tips are also super helpful for blondies! i’m always super impatient and want to cut into them right out of the oven, but letting them cool makes allll the difference.

  4. Omg! These look so good! You’re so lucky all you crave is fruit during your pregnancy. I’ve got about 5 weeks to go and all I crave are cheeseburgers and ice cream (and I pretty much used to hate both!) and my favorite ice cream to get… is Reese’s peanut butter cup so these look divine! Somehow I’ve kept my weight the same since before Easter but don’t ask me how haha!! Question.. in an attempt to re-organize (my entire house) my pantry, do you have any specific containers you recommend for storing flour, sugar, brown sugar, oats, etc. in? Labels would definitely help, too! Thank you :))

    1. that’s too funny that you didn’t care for either and now that’s all you crave! But I hear that’s quite common. I do crave a fair share of salty chips– like kettle cooked chips with lots of seasonings. Random!

      AS far as storing goes– yes. I have a suggestion for you! I swear by these containers. My husband bought me a couple earlier this year and I ended up ordering two more. I have 4 for my flour, sugar, brown sugar, and confectioners’ sugar. Kevin made little labels on top. You can see me using them in this live video and also in this post: https://sallysbakingaddiction.com/2017/01/13/coffee-break-13/

      1. So along those same lines….how do you store your sprinkles?? I’m a “for fun” baker with quite a sprinkles hoarding problem. (Although how could that be a problem?!) My husband and I just moved to a new house and I’ve been trying to figure out the best way to keep them all organized. Any tips?? Also, those containers are definitely on my “new kitchen wish list” haha!

  5. OMG Sally. I can’t believe you have outdone yourself. These are so on my menu this coming weekend. Your brownies are my favorite and have been for years but this is just…incredible ♡

  6. Jenny from jennyisbaking.com says:

    Haha, I think I will happily have the bikinis mingle somwhere with self-control while I eat a gigantic piece of this deliciousness! Thank you, we have company, I might make these right away.

  7. Patricia @Sweet and Strong Blog says:

    OMG how can you do this to me on a Monday!  Your brownie recipes are seriously to die for and I’m obsessed with anything chocolate and PB.  Love the swirl in these and can’t wait to try them!

  8. Sara @ The Ravenous Housewife says:

    Wow this looks amazing!

  9. Jenny from Jenny is baking says:

    Hey Sally, is it correct that you don’t use any baking soda or baking powder? Just wondering as I am making the recipe right now. 

    1. Yep! I don’t typically add leavening agents to brownies as I prefer a dense texture. 🙂

      1. Jenny from jennyisbaking.com says:

        Thanks for the quick reply. I trusted that you wanted it this way and just continued without.
        They are baking in the oven and I have our guests constantly popping by asking when they are done, lol. I don’t think I will manage to cool them, they will be gone soon.

      2. Jenny from jennyisbaking.com says:

        So just as a follow-up: the brownies are gone, they were a big crowd pleaser. Sally, as always thank you so much for yet another wonderful recipe!

      3. Ahhhh that’s wonderful to read. Thank you so much for taking the time to report back.

  10. These look incredible!

    www.bakesbybutter.com

  11. Tracy Groot says:

    Sally? I love you. 

  12. Looks beautiful and love the texture too!! 

  13. I’ve actually made the “skinny version” for myself & my family many, many times. We love it over here – would have no clue it’s “skinny.” That being said, there’s nothing quite like a traditional, super fudgy and over-indulgent chocolate brownie swirled with peanut butter. Glad I’m not the only peanut butter dessert lover around 😉

    1. Couldn’t agree more….and you definitely aren’t alone! 🙂

  14. One of my best friends is pregnant and due at the end of the month. She is also a HUGE peanut butter chocolate fan. I know what I’ll be making her when that baby comes!! Thank you!

  15. Laura @ The Bluenose Baker says:

    Oh my god those look delicious! It doesn’t help that I am stuck in my glider with a sleeping baby and I am starving! I haven’t had chocolate in like 2 months and I am absolutely dying for a brownie. I need to test if baby girl can tolerate chocolate or nuts in my diet yet so I can make these.

    1. Way to remain strong for your little girl! Hope she passes the tolerance test 😉

  16. Shawnna Griffin says:

    hey girl- these look so tasty!

  17. Wow, those brownies look super delicious!!!! Perfect for my husband’s coming birthday. Thanks for sharing:)

    1. Happy birthday to him! Enjoy!

  18. Oh boy, oh boy. Brownies with peanut butter. Is there a better combination? I don’t really want an answer . . . because there are some that are close anyway. Wait for it to cool completely before cutting? Really?! Have you smelled brownies as they come out of the oven? Not waiting . . . I don’t CARE what they look like. ~smile~

    1. Haha…I had to wait to make them pretty for photos! And yes the smell made it almost impossible!

  19. Shelby @ Go Eat and Repeat says:

    I can’t believe you haven’t posted any peanut butter swirl brownies before! They are such a classic treat! I whip them up all the time at home, especially since peanut butter and chocolate baked goods have become my latest obsession!

  20. Sally, it doesn’t say in the directions when to add the reserved peanut butter cups?? After I bake them?? These look absolutely amazing and thank you for not using unflavored baking bar! My husband can always taste them in brownies (even when after sugar is added and hates the taste of them) . Thanks for another great recipe!!!

    1. Right after you swirl the chocolate and peanut butter batters together you can sprinkle the pan with a couple leftover chopped peanut butter cups and then pop into the oven!

  21. I love chocolate and peanut butter! Thank you so much for this recipe, I just found your blog and am trying to make as many recipes as I can this summer!

    1. The summer of BAKING! I love it.

  22. Deb Allmeyer says:

    I don’t think I can resist this recipe!  I’m going make them when my son gets home from college so they will disappear somewhere else besides down my throat!!!
    I so appreciate how you respond to your commenters.  This has made your site (besides the fabulous recipes) my favorite!  If you would like to have the Chocolate Drop Cookie recipe, let me know where to send it!  You (and husband and baby) will love them!!

    1. Thanks so much Deb! And I’d love that recipe– you can email it to me at info(at)sallysbakingaddiction.com You are so thoughtful, thank you!

  23. Kelly @ Kelly Lynns Sweets and Treats says:

    Totally worth letting the bikini run away and putting the sweat pants on for 😉 

  24. These look A-MAZING. Adding them to my list. But here’s my one question – I noticed mention made in a comment earlier about leavening agents and how you don’t generally use them because you prefer denser brownies … I’m actually not as big of a fan of super dense brownies. Any suggestions for me that would get me your level of delicious but with a bit lighter brownie base?

    1. Maybe try adding 1 teaspoon of baking powder to the recipe when you add the dry ingredients. Let me know how you like them with that addition!

      1. So I baked a half-batch last night, using a few alterations. I added the baking powder as you suggested, and then after reading up on the food science differences between different brownie textures (fascinating stuff – your blog turned me on to all the science behind the kitchen scenes lol, so thanks) I also reduced the amount of butter slightly, added a bit of milk to the batter, and because I was splitting things in half and had an awkward egg measurement, I used one whole egg and one egg white. The brownie part turned out pretty good, actually. Unfortunately, my peanut butter swirl part got really dry. Basically a super crumbly mess when I tried to eat them. (Tried and succeeded because still delicious.) I still had moist crumbs on my toothpick when I took it from the oven so I didn’t think it was overdone, but perhaps? Either way, I had fun experimenting and the results, though not perfect, were still quite tasty. So I’m happy.

        (I’d also that very afternoon received new flour/sugar containers for my unbelievably chaotic baking cupboard and the organized result made me so happy, I can’t even tell you. So I just *had* to bake something, lol. Glad I had plans for this recipe already!)

      2. YAY!!! I’m glad you gave the recipe a try with your alterations. 🙂

  25. Kelly Senyei @ Just a Taste says:

    Drooling over how delicious these brownies look, Sally!

    1. Thanks Kelly!!

  26. aaaaaahhhhh! These were decadent.
    Thanks Sally!

    1. I’m glad you tried them already!!

  27. These look amazing Sally! My husband loves peanut butter so I’m thinking these are the perfect treat to make him for Father’s Day 🙂 Also, I love love love all your tips! I have plenty of plastic knives I now know what their purpose in life is!

  28. Random Tip Time: Trader Joe’s sells One Pound Baking Bars of high quality (imported from Belgium) Milk, Dark and White Chocolate. They’re a staple amongst my baking supplies.

    Just ran out of peanut butter this morning (still packing school lunches, anyone?), so I’m going to make these with almond butter tomorrow!

    1. I LOVE TJ’s pound plus choc bars!! Such a steal of a price too.

  29. If I melt down these Guittard dark chocolate chips, do you think it would work as a substitute for the semi-sweet chocolate bar? I know they’re not the same, but don’t want to run to the store again!

    1. They *may* work because they’re wonderfully high quality, but pure chocolate bars are best!

  30. Paula Jarrett says:

    Awesome recipe!! The plastic knife has been my trick for years now!! I first started using one though because I figured it was the best thing to use to avoid making scratch marks in my (non-stick) type pans!! I have baking pans that are now 20 yrs old without a single scratch because of this little trick!!

    1. So smart!

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