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

peanut butter swirl brownies

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.

overhead image of a jar of peanut butter

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.

peanut butter swirl brownies on a cream plate

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’!

3 images of skinny peanut butter swirl brownies

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.

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peanut butter swirl brownies

Skinny Peanut Butter Swirl Brownies

  • Author: Sally
  • Prep Time: 10 minutes
  • Total Time: 3 hours, 10 minutes
  • Yield: 1216 brownies 1x
  • 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 (41g) 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.

Keywords: skinny peanut butter swirl brownies

Reader Questions and Reviews

  1. These were amazing!!! I am recently gluten free but I am a sucker for baking and was so excited to find this recipe. I cannot wait to try out more of yours in the future 🙂

  2. I made these tonight and they turned out great! For the 1 cup of sugar, I used the following: 1/4 cup honey, 1/4 cup light agave syrup and 1/2 cup coconut sugar.

    I used cacao powder instead of cocoa powder AND I also through in 1 scoop of chocolate protein powder. The batter was really runny so I through it in the fridge for an hour before baking. They stayed in the oven for about 30 minutes and turned out more cakey than fudgy, which is how I like my brownies!
    Thanks for the recipe!

    1. Typo – it was 1/8 cup of honey and 1/8 cup of light agave syrup

  3. Hi Sally!

    I want to make these but my blender is on the fritz. I’m guessing a mixer won’t do the trick?

  4. Hi Sally. I made these last night and doubled the recipe. I used a 9×13 pan and baked for 26 minutes. They taste good but so moist I’m wondering if they are actually fully cooked. Since they are so fudgy, how can I tell?

  5. Hi Sally,
    A few questions about the recipe. I made these recently and they are exquisite, but more like fudge. I agree with  one of the resposns, that they are so moist. They took 40 minutes in my oven before they were done. And I have to use a fork because otherwise the chocolate sort of melts in your hand. The taste is wonderful, but I am wondering how to change the measurements…more oats-less yogurt(?) to  achieve a shorter baking time and a little bit less fudgey and more brownie texture, more like your ‘seriously chocolate  fudgey brownies’  I would really appreciate your advice. Thanks…

    1. For that, I would simply begin testing different ratios. Start with a small reduction of yogurt and a slight increase in oats. I’m unsure of exact measurements though, but let me know what you test out. I’m glad you love them!

  6. I made made these last week, though I didn’t read the recipe properly and mixed the peanut butter in with everything else. I also decided to use quick oats, chunky peanut butter (because I was out of smooth) & mixed by hand instead of the blender. I know it’s not technically following your recipe when I do it that way, but to my surprise it worked! The taste is awesome. Next time I’ll definitely read the instructions more carefully.

  7. I’ve made this recipe multiple times, and it always turns out well! I’ve used both creamy peanut butter, and also replaced the peanut butter with PB2 powdered peanut butter mixed with water. Of course it’s not quite as good as peanut butter, but works as a lower calorie option!

  8. Oh my gosh I just made this – midnight chocolate cravings with limited ingredients – and it is INCREDIBLE! I couldn’t wait for it to cool – the taste and texture are perfect. I’ve already had two helpings (warm with cream) – delicious! Thank you!

  9. Oh my gosh I just made this – midnight chocolate cravings with limited ingredients – and it is INCREDIBLE! I couldn’t wait for it to cool – the taste and texture are perfect. I’ve already had two helpings (warm with cream) – delicious! Thank you!

  10. Hi! I do not currently have rolled/old fashioned oats at home and I have checked quite a few local grocery stores and have not been able to find them, would it be possible to use quick oats or quick steel cut oats in them?

    1. Hi Kianna, you can certainly use quick oats! Hope you enjoy these brownies!

    1. Hi Nicola, I’m unsure of the nutritional info of this recipe, but there are many great online calculators like this one:

    1. Hi Andy, We haven’t tested this recipe using cacao powder and it would take some recipe testing for us to be confident of how to alter the ingredients. Let us know if you try anything!

  11. I’ve made these twice this week for friends. They’re great. I made just as the recipe says except: plus 1 scoop of vanilla whey protein powder and cooked for closer to 30 min until a tooth pick was mostly clean.
    Perfect brownie texture.

  12. I have to say I was skeptical at first about the process and the ingredients of these brownies. I am so glad I made them. Oh my god, they were so good! My husband said these are the best brownies I ever made. Thank you Sally for this recipe. I know I will be making these again. ❤️