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Skinny Peanut Butter Brownies

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Skinny peanut butter brownies are made with a lightened up brownie mix, and topped with a peanut butter and marshmallow creme topping.

peanut butter brownie slice on a white plate

I sometimes refer to this recipe as two ingredient brownies. They start out with a simple boxed sugar-free brownie mix, but rather than adding eggs and oil, I add Diet Coke. It’s crazy to think that adding just cola to a brownie mixture can make brownies, right?

The batter won’t be quite as thick as making the brownies according to the box, but it bakes into fluffy, delicious brownies.

I add some peanut butter powder into marshmallow creme, then use it to top the brownies in a nice, thin layer. It’s the perfect pop of creme and peanut butter!

chocolate peanut butter brownies on a wire rack covered in marshmallow cream frosting

Why you’ll love this recipe

  • Brownies with less calories
  • A guiltless way to indulge in a sweet treat
  • Made with a boxed mix for less fuss
  • Topped with a delicious peanut butter marshmallow creme
chocolate peanut butter brownies cut in half on a wire rack

Ingredients 

What you’ll need to make this recipe.

peanut butter brownie slice on a white plate

How to make this recipe

1 – Preheat the oven to 350 degrees. Spray an 8×8-inch baking dish with nonstick cooking spray.

2 – Add the brownie mix and Diet Coke to a medium sized mixing bowl and mix together with a wooden spoon. Be careful to not over mix. Brownie mix will be runny. 

3 – Pour the brownie batter into the prepared baking dish. Bake for 35-40 minutes, until brownies are cooked through. Use a toothpick to check center. Allow brownies to cool completely.

4 – In a small bowl, add the peanut butter powder and water and mix together. Add the marshmallow creme and together mix again. 

5 – Spread mixture evenly over brownies. Enjoy!

peanut butter brownie slice on a white plate

How do I store my leftover brownies?

Place brownies in an airtight container and store on the countertop for 3-4 days.

Calories per serving (1/12 serving): 127

Yield: 12 Servings

Skinny Peanut Butter Brownies

peanut butter brownie slice on a white plate

Skinny peanut butter brownies are made with a lightened up brownie mix, and topped with a peanut butter and marshmallow creme topping. Perfect for a guiltless treat.

Prep Time 15 minutes
Bake Time 35 minutes
Total Time 50 minutes

Ingredients

  • 12.35 ounce Pillbury sugar free brownie mix
  • 12 ounces Diet Coke
  • 2 tablespoons peanut butter powder
  • 1 tablespoon water
  • 4 ounces marshmallow creme

Instructions

  1. Preheat the oven to 350°. Spray an 8x8-inch baking dish with nonstick cooking spray.
  2. Add the brownie mix and Diet Coke to a medium sized mixing bowl and mix together with a wooden spoon. Be careful to not over mix. Brownie mix will be runny. 
  3. Pour the brownie batter into the prepared baking dish. Bake for 35-40 minutes, until brownies are cooked through. Use a toothpick to check center. Allow brownies to cool completely.
  4. In a small bowl, add the peanut butter powder and water and mix together. Add the marshmallow creme and together mix again. 
  5. Spread mixture evenly over brownies. Enjoy!

Nutrition Information:

Yield:

12

Amount Per Serving: Calories: 127Total Fat: 2gSaturated Fat: 0gTrans Fat: 0gUnsaturated Fat: 0gCholesterol: 0mgSodium: 100mgCarbohydrates: 32gFiber: 4gSugar: 6gProtein: 1g

Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.

Did you make this recipe?

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Other recipes you’ll love

American Flag Skinny Cake

Skinny Funfetti Poke Cake

Whipped Topping Ice Cream Sandwiches

Lemon Cake With Pineapple Filling

Chocolate Cupcakes With Whipped Chocolate Frosting

I’d love to hear your thoughts. Comment below or tag me on Instagram. And don’t forget to Pin it for later!

skinny peanut butter brownies pin
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Cool Cook

Sunday 19th of July 2020

I'm not sure the sweetener in diet coke is heat-stable. So I'm leery of doing that. I might try this with unsweetened Seltzer water, though.

simplylowcal

Monday 20th of July 2020

I've never tried using seltzer water. Let me know how it goes. :)

Gloria

Tuesday 7th of July 2020

I love the peanut butter chocolate combo. A healthier version of the classic treat is perfect. Now I can enjoy it when I crave something sweet.

simplylowcal

Wednesday 8th of July 2020

Thanks, Gloria. I hope you enjoy them. :)

Sharon

Tuesday 7th of July 2020

I've never seen diet coke in brownies!! I have a friend who LIVES for diet coke. She's going to love this recipe. :)

simplylowcal

Wednesday 8th of July 2020

That's great, Sharon! I hope she enjoys it. :)

Lizet Bowen

Tuesday 7th of July 2020

I think everybody needs a recipe like this one. Skinny chocolate peanut butter brownies! to die for. :)

simplylowcal

Wednesday 8th of July 2020

Thanks, Lizet! :)

Kushigalu

Monday 6th of July 2020

These brownies look fantastic. One of the best combination ever. Thanks for sharing

simplylowcal

Monday 6th of July 2020

Thanks, Kushigalu. :)

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