Skinny Peanut Butter Swirl Brownies

A skinny option for peanut butter brownies. Super fudgy brownies made without white flour, butter or oil!

Skinny Peanut Butter Swirl Brownies! Gluten-free, made with whole-grain oats, no flour, no butter, no oil, and with a ton of sugar substitute suggestions! These are so fudgy, you won't miss the unhealthy ingredients!

Oh my word. Do I have a treat for you guys today.

I honestly think I am dreaming because today not only am I bringing you the fudgiest, richest, softest, chewiest brownie I have EVER eaten,  I am bringing you a fudgy, rich, soft, chewy, and SKINNY brownie swirled with my one true love (sorry, Kevin): peanut butter.

Skinny & brownie in the same title is a tad ironic, but I am telling you friends… you are not dreaming.

As I begin to train for the Baltimore half marathon coming up in 4 months (anyone else out there running that? let’s be friends), I knew I needed a little treat to put some pep into my running step. Preferably something tasting sinfully chocolatey and smothered in peanut butter because, well… why not.

Most brownie recipes call for loads of butter or oil, white flour, excessive amounts of sugar, and 3+ eggs. Hence, their wonderfully decadent + rich taste. These skinny brownies, however, combine much healthier alternatives, making these brownies good enough to call breakfast. Instead of clogging the brownies with butter and oil, which would inevitably slow me down and have me feeling lethargic, I loaded the brownie batter with low fat vanilla greek yogurt. It gives these brownies that unbelievable moist and fudgy taste that I love in my favorite not-so-healthy chocolate brownies.

In fact, these brownies are so rich and fudgy that someone even told me they tasted like straight up chocolate/peanut butter FUDGE! I can’t even believe there is no oil, butter, or flour these.

Skinny Peanut Butter Swirl Brownies! Gluten-free, made with whole-grain oats, no flour, no butter, no oil, and with a ton of sugar substitute suggestions! These are so fudgy, you won't miss the unhealthy ingredients!

In addition to the low fat greek yogurt, I used fiber-rich, whole grain oats instead of white flour – whole grain carbs are a perfect way to start your day and/or fuel a workout! The recipe only calls for 1/2 cup of oats which are ground up into a flour. A brownie’s fudginess directly relates to the amount of flour in the recipe. And with only 1/2 cup of ground up oats in the entire recipe, you can imagine the density and fudginess of these babies!

My recipe has white sugar, but you could easily use 1/2 cup of honey instead. Some readers have even used Truvia, a mix of 1/2 cup brown sugar and 1/4 cup honey, or even 1/2 cup sugar and 1/2 cup dates instead of the 1 cup of white sugar. I’ve used coconut sugar instead which works wonderfully too. No matter how you chose to sweeten it, taste the batter to make sure it is sweet enough.

And to put these brownies completely over the top, I threw in a THICK peanut butter swirl because I firmly believe that there is nothing better in this world than chocolate and peanut butter. Peanut butter is full of healthy fats and protein… perfect for shiny hair, glowing skin, and keeps your muscles workin’!

You will not believe these fudgy peanut butter swirl brownies are lightened-up! Learn how to make them at

So today, here is your recipe for what may the BEST brownie you’ll ever taste. AND a brownie you can actually feel good about eating!

See more of my healthy recipes.


Skinny Peanut Butter Swirl Brownies

  • Author: Sally
  • Prep Time: 10 minutes
  • Total Time: 3 hours, 10 minutes
  • Yield: 12-16 brownies
  • Category: Brownies
  • Method: Baking
  • Cuisine: American


A skinny option for peanut butter brownies. Super fudgy brownies made without white flour, butter or oil!


  • 3/4 cup (185g) creamy peanut butter*
  • 6 ounces low fat or fat free plain or vanilla Greek yogurt
  • 1/4 cup (60ml) milk (I like to use unsweetened almond milk)
  • 1 large egg (or 2 egg whites)
  • 1/4 teaspoon salt
  • 1 teaspoon baking powder
  • 1 cup (200g) granulated sugar or coconut sugar (see note above in post about substitutions)
  • 1/2 cup (42g) unsweetened natural or dutch process cocoa powder
  • 1/2 cup (40g) old-fashioned rolled oats*


  1. Preheat oven to 350°F (177°C). Spray a 8×8 inch pan with non-stick cooking spray. Set aside.
  2. Place all of the ingredients except for the peanut butter into a blender or food processor. (Yes, a blender!) For easier blending, place the liquid ingredients into the blender first. Blend until mix is smooth and oats are ground up. You will have to stop the blender and scrape down the sides a few times.
  3. Pour batter into prepared baking dish. Batter will be thin. Microwave peanut butter for about 30 seconds. Drop melted peanut butter by spoonfuls onto the batter, swirling gently with a knife to create a marbled effect. (Try not to overmix!)
  4. Bake for 20-25 minutes or until brownies begin to pull away from the sides of the pan. Brownies will be extra fudgy, so be sure to wait until COMPLETELY cooled – I stuck mine in the refrigerator for 2 hours, which allowed them to be cut very easily. Cut into squares and enjoy!


  1. Make Ahead & Freezing Instructions: Brownies stay fresh at room temperature for 2 days, and then can be stored in the refrigerator for up to 5 days after that. Brownies freeze well up to 2-3 months.
  2. Peanut Butter: Do not use natural, runny peanut butter or powdered “peanut butter”
  3. Oats: Make sure oats are certified gluten free if gluten intolerant.
  4. Nutrition: Curious about the nutrition facts? Visit a calorie counting website with your specific ingredients/brands to determine!
  5. Adapted from Dashing Dish.


  1. I used 1/2 of a banana instead! They turned out fine, just a bit of a tropical flavor added!!! Yum! I love your recipes, Sally! I drink the banana strawberry smoothie all the time!

  2. I have to say, I have made other healthy brownie recipes before. I am always trying new recipes to indulge while following a healthy eating plan for my family.
    These were by far thee very best ones I have literally ever tried. I can honestly say that if someone didn’t even tell me they were healthy, I would have never guessed. The fact that they are also gluten free (as long as your oats are gluten free) is amazing! My son has Autism and he can eat these. He loved them!! Thanks so much for this awesome recipe. It’s a keeper!!

  3. These were delicious! I loved them…. Like many, my. New Years resolution was to increase my gym activity and eat “clean”. Three weeks in I am doing great and this recipe will certainly help. My favorite dessert is anything chocolate and peanut butter and this fit the bill. I am glad I found this.

    The only alteration I made with this recipe was replacing the sugar with honey and brown sugar and it worked perfectly.
    Thank you!!

  4. Made these uber fudgy brownies last night during the snow storm in New Jersey. Wow is all I have to say. They are so good, I feel like I am eating a piece of pb fudge. The whole family loves them!

  5. Hmm, these looked awesome and delicious on here, but they had a funny taste I did not enjoy at all made. I tried these a few times to make sure it wasn’t a one time mistake 🙁 to bad, they looked incredible.

  6. I made these brownie yesterday for a Super Bowl Party and they were a big hit! Love them! I love the mixture of chocolate and peanut butter and since I am doing Weight Watchers this allowed me to have my chocolate and peanut butter with no guilt.

  7. Hi Sally, I’m so excited to try these, but wondered if you needed to use a blender or if I use quick porridge oats (much finer than whole oats), or wizz the oats up first could I do the rest in a mixing bowl? Or do you need to really blitz the whole recipe to combine it right? It’s only because I have a tiny blender thing and there’s not enough room for the whole recipe in there 🙂 Thank you

    1. Hey Louisa! Just process/pulverize your oats into a fine powder-like consistency. You’ll also want to beat the egg beforehand. Then combine it all by whisking the batter. Enjoy!

  8. Hi Sally! I have some leftover cookie butter that I’d like to try to use up… What do you think of subbing cookie butter for the peanut butter? Too sweet? Clearly they wouldn’t be flourless or gluten free anymore but…I’d like to try the cookie butter chocolate combo because I never have before and I find the cookie butter VERY sweet so I thought the bitterness of the cocoa and maybe a little bit less sugar with this recipe would be good. Let me know what you think! Thanks! 🙂

  9. Sally!, what a delicious recipe!! I baked this little beauty today and what a great result. No doubt due to the recipe not my baking skills! I substituted the sugar for a quarter cup of agave syrup and it turned out great. Can’t wait to try the healthy cheesecakes next!! Thanks for all the ideas, motivation and gorgeous photography Sally please keep it up!!

  10. I made these last night & can’t get over how good they are! So moist and fugdy. I just recently started reading your blog and now I can’t wait to make all of your “skinny” recipes. Thank you so much!

  11. Hey, I was planning on making these for my friend’s birthday today! I was wondering if it would change the recipe too much if I substitute all purpose flour for oats?

  12. I never usually leave a comment but I made these last night and they were fabulous! I did use brown sugar to substitute a little white sugar and then I used regular vanilla nonfat yogurt since that’s all I had on hand. But they ended up looking just like yours, I will definitely make these again! Thank you!

  13. This was a great recipe! You inspired me to experiment even further. I didn’t deviate from your recipe the first time, and then played with it a 2nd time. To give it a more nutritious ‘punch’ I substituted your cup of sugar for a cup of mashed sweet potatoes (precooked), and instead of 1/2 cup of cocoa powder I used 1/2 cup of whey (some could use soy) protein. I also added a 1/4 cup of chia seeds.

    Thanks for the inspiration.

    1. OOOOooo…I will have to try that sweet potato substitute-yum!!..did the sweet potatoes moisture interfere with the recipe? Mine always come out super fudgy with just the 1c sug, but I would love to experiment to cut back.
      Thx for sharing!

  14. Wow Sally…just wow/ I just got done making these and holy crap! I used 1/2 cup of honey instead of the sugar and you’d never guess that there is no butter or four or sugar in them. They are so incredible! And it is s o hard to feel guilty for eating one since they are made with all natural ingredients! This recipe was one of the most incredible ones that I have ever made and it absolutely made my day. Even my grandmother (who has the biggest sweet tooth on this planet) said they were amazing. So I just wanted to thank you. They were amazing THANK YOU I WILL DEFINITELY MAKE THESE AGAIN! 🙂 You really are the absolute best Sally!

    1. I’m so happy you love these brownies, Rachael! I make them quite often. My fiancé never can tell the difference between these and my butter-laden brownies!

  15. These are fantastic! I used 1/2 cup raw sugar and a large ripe banana for sweetness + a handful of 60% cocoa dark chocolate chips. So glad i found this recipe!

    This is a real keeper.

  16. I loved the idea of putting dates in but I only had prunes. They are soooooooo good!!! These will be a staple in our house for sure!!

  17. I would LOVE to make these, however, with my nut allergy I would have to use sunflower butter. Would that work or would it be too runny?

  18. I have made these brownies several times now and I have to say they are so incredibly fudgy! I don’t include the peanut butter as I’m having a hard time finding peanut butter which will actually melt in the micro instead of going frothy/mousse like. I have a batch in the oven right now actually, but I’ve substituted Stevia for the sugar as an experiment to see if this recipe can produce truly guilt free brownies!

  19. Hi! I’ve recently discovered your blog and am now IN LOVE with it! I tried these peanut butter swirl brownies, and they are amazing! Really easy to make too! The only hard thing indeed was waiting for them to cool before diving in!

    Can’t wait to try your other recipes! 🙂

  20. I made your somewhat similar peanut butter swirl chocolate snack cake from the cookbook today, and the one issue I had was that when I tried melting the peanut butter in the microwave, I think it got overcooked, then it was dry and crumbly and wouldn’t melt. I started that part over and melted new PB on the stove over low heat. When you melt PB in the microwave, do you do it at full power? I was using Skippy Reduced Fat Creamy Peanut Butter.

    1. Yes, I do it at full power. I’ve never had an issue. I know the stovetop works like a charm as well. All microwaves are different and quite temperamental when it comes to melting PB or chocolate.

      1. Thanks for the response 🙂 I wonder if the fact that the PB was reduced fat affected how it melts. Aside from the mishap with the PB, I loved the recipe. The snack cake came out moist and delicious.

  21. I just made these brownies in search of a recipe that is healthy and delicious that my whole family would enjoy. I used Skippy All Natural PB, 1/2 cup stevia and about 1/4 cup honey. I loved it(especially the peanut butter!), my 8 year old daughter enjoyed it and my husband (hater of most things “healthy”) liked it and said he could eat them over the full sugar & fat alternative. Successes!

    Thank you!!

  22. Hi Sally,

    Thanks for posting this recipe. I really want to try it (#peanutbutterlover), but my brother has a peanut allergy. Do you think I can still make these without peanut butter?

  23. Hello Sally! I want to make these for my friend’s birthday party but don’t have any baking powder. Could I sub in baking soda instead?

  24. Absolutely gorgeous recipe! One of my favourites for my gluten free friends, the brownies still tastes so decadent but with much more of the good stuff. Thank you Sally! Love your healthy recipes just as much as the naughty ones!

  25. I absolutely cannot wait to see how these go! Is it essential to use Creamy peanut butter? or can one use crunchy instead?
    thank you x

  26. Finally tried these last night and I love them! There was no way I could wait 2 hours so I stuck them in the fridge for 30 min and had a good gooey piece. This morning, they cut perfectly. Yum!

1 4 5 6 7 8

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

With kitchen-tested quality recipes and step-by-step tutorials, my goal is to give you the confidence to bake and cook from scratch.

Sally's signature

Recipes You’ll Love



Join the community on the 1st of every month as we tackle a new challenge recipe. Review Sally's Baking Challenge FAQ page if you have any questions.

View More

A tradition since 2013, every December we countdown to Christmas with 10 new cookie recipes in a row!

View More

The first week of every November is all about Thanksgiving Pies.

View More

My Cookbooks

Sally's Cookbooks

About Sally

Welcome to my Kitchen!

I’m Sally, a cookbook author, photographer, and blogger. My goal is to give you the confidence and knowledge to cook and bake from scratch while providing quality recipes and plenty of pictures. Grab a cookie, take a seat, and have fun exploring! more about Sally