5 from 4 votes

Homemade Cosmic Brownies

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Homemade Cosmic Brownies, the trendy dessert of your childhood, are easier than you think at home. With a thick chocolate frosting and candy-coated chips topping, this dense, rich, and perfect copycat brownie can be duplicated with little effort and fun.

 Coming in a close second to the original recipe, this ultra fudgy treat is irresistibly out of this world!

copycat little debbie cosmic brownies.

Why you will love making TikToks Cosmic Brownies

Nostalgia Childhood Lunchbox Throwback –  These delicious fudgy and dense brownies were the lunchbox dessert of the 90s. Ripping open a package of the little brownie and enjoying that burst of chocolate flavor was one of the best parts of grade school. 

Making them at home may not be as easy as grabbing a storebought box (nothing is), but this copycat recipe is worth the effort for one of your homemade childhood favorites.

tiktok cosmic brownie being held.

Where did this Fudgy Brownie recipe come from?

While there are many viral dessert recipes and even recipes for brownies, we got this awesome throwback brownie recipe from TikTok Creator Petroutv – which looked amazing.

You can his video of this classic chocolate treat that popped up on our FYP below: 


I made cosmic brownies at home

♬ original sound – Thomas Petrou

Did we enjoy TikToks Cosmic Brownie recipe? 

I think it’s pretty hard not to enjoy fudgy brownies.

These were fun to make and super delicious, but I’m a little bummed the chocolate ganache didn’t a little harden more like the real cosmic brownies. The frosted brownies of my youth have more of a creamy ganache that sets a little bit – but it could likely be the preservatives in the ingredients change.

Still, these copycat cosmic brownies are a close second, extremely rich, and have a fantastic taste. 


Brownie ingredients

  • unsalted butter
  • granulated sugar
  • brown sugar
  • eggs
  • vanilla extract
  • vegetable oil
  • all-purpose flour 
  • cornstarch
  • unsweetened natural cocoa powder – It is essential to use high-quality cocoa powder for the best flavor. 
  • baking soda

Chocolate Fudge Topping

candy coated rainbow chips.

How to make Homemade Cosmic Brownies

  1. Preheat the oven to 350, line a 9×13 baking pan with parchment paper and spray with nonstick cooking spray. Set aside. 
  2. Add melted butter, sugars, eggs, vanilla, and vegetable oil to a mixing bowl and mix well. Set aside. 
  3. In a separate medium bowl, combine flour, cornstarch, cocoa powder, a pinch of salt, and baking soda and mix well.
  4. Add dry ingredients to wet ingredients and mix until combined. It is not necessary to overmix. 
  5. Pour into prepared pan. A rubber spatula can assist in getting all batter off the sides of the bowl.
cosmic brownie batter being made.
  1. Bake for 24-26 minutes or until the edges begin to brown. Remove from oven and cool completely. 
  2. Add chocolate chips, milk, and butter to a saucepan and heat over low heat, constantly stirring until smooth and shiny.
  3. Cool slightly before pouring chocolate brownie frosting on top of the brownies.
  4. Top with rainbow chips. Cool and refrigerate for an hour. 
  5. Remove parchment paper and brownies from the pan and cut them into 24 bars.
  6. Store leftover brownies covered in the refrigerator in an airtight container. 
tiktok cosmic brownies.

How to avoid crumbly brownies

While this homemade version of a childhood favorite recipe is very specific, baking can be challenging for some.

To ensure no surprises with the result of a recipe, be sure to measure precisely and adjust baking times as necessary for your oven. 

5 from 4 votes

Homemade Cosmic Brownies (TikTok Version)

Prep Time 15 minutes
Cook Time 26 minutes
Fudgy and rich, these homemade cosmic brownies are a throwback to Little Debbies Cosmic dense brownie treat! Viral TikTok recipe.



Brownie Mix

  • ¾ cup melted butter
  • granulated white sugar
  • ½ brown sugar
  • 3 eggs
  • 1 egg yolk
  • 1 tsp vanilla extract
  • ¼ cup vegetable oil
  • 1 cup flour
  • 2 tbsp cornstarch
  • cup unsweetened cocoa powder
  • 1 tsp salt
  • ¼ tsp baking soda

Chocolate Frosting


  • Preheat the oven to 350 and line a 9×13 baking pan with parchment paper and spray with nonstick cooking spray. Set the baking pan aside. 
  • Add melted butter, white and brown sugar, 3 eggs and egg yolk, vanilla extract, and vegetable oil in a mixing bowl and mix well. Set bowl aside. 
  • In a separate mixing bowl, combine all-purpose flour, cornstarch, cocoa powder, salt, and baking soda and mix well.
  • Add dry ingredients to wet and mix until combined. Pour brownie batter into the prepared pan.
  • Bake brownies for 25 minutes or until edges begin to brown.
  • Remove baking dish from oven and cool completely. 
  • Add chocolate chips, milk, and butter to a saucepan and heat over low heat, stirring constantly until frosting is smooth and shiny.
  • Cool topping slightly before pouring on top of baked brownies.
  • Top with rainbow chips.
  • Cool and refrigerate brownies and frosting for an hour. 
  • Remove parchment paper and brownies from the pan and cut into 24 bars.
  • Store leftover cosmic brownies covered in the refrigerator.


We always suggest pre-measuring and prepping ingredients prior to beginning the recipe. This ensures proper wet and dry ingredient measurements and have the best baking results. 


Serving: 1brownie | Calories: 132kcal | Carbohydrates: 16g | Protein: 4g | Fat: 7g | Saturated Fat: 4g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 2g | Trans Fat: 1g | Cholesterol: 30mg | Sodium: 125mg | Potassium: 189mg | Fiber: 3g | Sugar: 6g | Vitamin A: 62IU | Calcium: 31mg | Iron: 2mg

Nutritional Disclaimer: The nutritional data provided here is auto-calculated and intended for your convenience only. As it’s generated via automation, its accuracy may be compromised. For precise nutritional insight, please compute the values utilizing the actual ingredients in your recipe through your chosen nutrition calculator or application.

Sharing of this recipe is encouraged and appreciated. Copying of full recipe to any social media is prohibited.

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5 from 4 votes

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Recipe Rating


  1. 3/4 butter – cup? stick?
    Step 2 in the instructions talks about using melted butter, but there is no direction before that. I can guess it’s 3/4 cup melted butter but a proper recipe should have that outlined for beginners? Thanks!

    1. Trisha Haas says:

      Its in the recipe card and its 3/4 cup butter, melted. The volume of melted butter or solid butter is actually the same. Its just that you need it to be melted before adding to the recipe.

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