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. Unfortunately these didn’t work out for me at all. They turned out super super gooey so I cooked them for longer and they were still so gooey. So I stuck them in the fridge like you said and even when I took them out they weren’t fudgy at all! I don’t know what went wrong. 🙁

  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!

  3. WOW! I made these last night and although I love LOVE peanut butter, I had to leave it out as the rest of my fam aren’t fans…BUT, everyone chose their fav Halloween candy & we carefully arranged them separately  in the pan. I chose PB Cups, of course!
    Because I wanted to eat them right away I added an extra handful of oats to help solidify the brownies. I also used 3/4 C maple syrup instead of sugar. 
    We were able to eat these directly out of the even with a dalop of ice cream & we regurgitated the rest….which is where where the WOW factor comes in.
    I decided to try one this morning just because and OMG! These are like a deep dark fudge dream! It almost tastes like there’s coffee in here  🙂 I also used a high quality chocolate powder. 
    I am keeping this recipe for eva!! 

  4. Looking forward to adding these to my list of get-healthy-again recipes for January! They look so fudgy!

  5. I just had to chime in here that these brownies are also fabulous when you add a scoop of vanilla protein powder to the brownie batter! I wanted to try it because I’m pregnant and my doctor told me to have more protein snacks during the day to keep my blood sugar stable. Naturally I’m looking for snacks that involve chocolate. And peanut butter. I used a combination of agave and stevia for the sugar, and vanilla whey protein powder. They’re not quite as fudgey-gooey as when I’d previously made them without the protein powder, but they do hold up better in a lunch bag, and they still taste fudgey and delicious. My baby thanks you. 🙂

  6. Hello. Just found your website and would have loved to make the peanut butter swirl brownies. I wish you would have posted the nutritional info without me having to figure it out. Been there done that and it’s a bother. I won’t try any recipe that doesn’t have the nutritional info posted.

  7. 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?

  8. I’m wondering about a non-dairy sub for the yogurt. Do you have a suggestion? Applesauce? Black beans? Coconut oil? More egg? Not sure what is needed instead.

  9. 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!

  10. I made these with 1/4 cup Truvia, twice the oats, and half the peanut butter. They are very good. They aren’t like a traditional gooey brownie (maybe because of my substitutions) but are more like ‘food’. I will make these again.

  11. 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.

  12. 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!

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