These homemade Cosmic Brownies are the perfect copycat Little Debbie Cosmic Brownies. They are thick, fudgy and moist, with a perfectly rich layer of chocolate ganache and cosmic candies sprinkled on top. 

You’ve probably figured out that I’m a huge brownie fan by how many brownie recipes I’ve posted for you guys. My Nutella brownies are a huge hit, so I’ve slowly been posting more brownie recipes for you to enjoy. Some of my favorites are my German chocolate brownie bars that are topped with the gooey coconut pecan frosting, my copycat BYU mint brownies, and my lunch lady brownies.

A Cosmic Brownie with a bite taken out of it.

Why This Recipe Works

  • Whether it’s fudgy brownies or brownie cookies, my favorite thing about brownies is the rich chocolate flavor and the creamy thick texture. And this cosmic brownies recipe delivers on both of those fronts. 
  • The brownie batter has a bit of cornstarch in it which gives us that thick, dense chocolate bar we love. Topped with a rich, creamy ganache, you just really can’t go wrong!
  • We use a chocolate ganache and not chocolate frosting. Smooth homemade chocolate ganache is way better on these brownies — and any brownie for that matter — because it is rich, creamy and isn’t overly sweet. With frosting, I always feel like I’m scraping some off, but not with ganache! Plus, I provide the perfect tips and tricks to get perfectly smooth ganache.
  • We line the pan with foil, so removing the brownies and cutting them is hassle free and easy.

Ingredients

Ingredients used to make cosmic brownies on a white background.

Cosmic Brownie Ingredients

  • Granulated Sugar: Using granulated and brown sugar is important since each has different roles, providing different colors, texture and flavors to the brownies. 
  • Light Brown Sugar: Can use dark brown sugar, it will just have a richer taste and adds moisture and flavor. 
  • Unsalted Butter: We use melted butter instead of softened butter. What’s its role in the brownie? Using melted butter in brownies contributes to the fudgier and more chocolatey flavor. 
  • Egg Yolk: Adding an egg yolk (in addition to the whole eggs used) works as a binding agent. The addition of an extra egg yolk also makes the brownie fudgier as well. Vanilla Extract: Using vanilla extract balances the flavor so it isn’t overly chocolatey.
  • Flour: The starch base for our brownies
  • Cocoa Powder: The cocoa powder is our source of rich chocolate for these brownies. I use unsweetened cocoa powder.
  • Cornstarch: Adding the cornstarch to the brownie batter helps thicken the mixture and creates that dense and creamy brownie base.
  • Rainbow Chips: These are a bit different from mini colored M&Ms, but you could also use those if you can’t find the rainbow chips. You can find rainbow chips on Amazon, here.

Homemade Chocolate Ganache Ingredients

  • Semi-Sweet Chocolate: Chopped (or you can use chocolate chips)
  • Heavy Cream: Heavy Whipping Cream is the same thing.

Step-by-Step Instructions

How to Make Cosmic Brownies

  1. Line the pan with either sprayed foil or with parchment paper.
  2. In the bowl of a stand mixer, beat the melted butter, brown sugar, and sugar on medium speed for 3 minutes.
  1. Add the eggs and egg yolk, one at a time, beating after each addition. Then add the vanilla and mix again.
  1. Whisk the dry ingredients together in a small bowl.
  2. Add the dry ingredients to the wet ingredients and mix until just combined. The batter will be quite thick, so don’t worry.
  1. Using a spatula, spoon and level the batter so that it’s in an even layer in the pan.
  2. Bake for 20-25 minutes. When the brownies are almost done, start making the ganache.

How to Make Ganache for Cosmic Brownies

  1. Place the chopped chocolate, or chocolate chips, in a medium-sized, heat-proof bowl.
  2. In a small saucepan over medium heat, warm the heavy cream to a simmer; once it’s almost boiling, remove from the heat and pour the heavy cream over the chocolate. Add a pinch of saltLet the heavy cream sit over the chocolate for 3 minutes before stirring.
Chocolate chips and heavy cream in a bowl for making ganache.
  1. After 3 minutes, use a small whisk and slowly begin whisking the cream and chocolate, starting in the center of the bowl and slowly moving towards the edges.

A whisk in a bowl full of chocolate ganache.

  1. Once smooth, let the ganache sit for 4-5 minutes and then pour it over the brownies and spread it into an even layer with a spatula.
  2. Once you have the ganache in an even layer over the brownies, sprinkle with rainbow chips.
  3. Allow the ganache on the brownies to set before cutting and serving. Place in the fridge to speed up the setting process.

Recipe Tips

Brownie Tips

Don’t over bake. The biggest culprit to dry brownies is over-baking them! All ovens vary. The brownies are done when a toothpick comes out with moist crumbs. 

Remove from the oven and let brownies cool in the pan. Note: they don’t need to be fully cooled before spreading the ganache overtop, but the brownies should be on the cooler side.

Be sure to whisk the dry ingredients together in a separate bowl. Since you have the cornstarch in there, you really want to make sure all the dry ingredients are incorporated evenly. This will help when mixing the dry ingredients into the wet ingredients for a more even dispersion of the cornstarch — resulting in a thick consistency across the entire pan.

Ganache Tips

You can use 1 1/4 cups of chocolate chips OR finely chopped chocolate. I used chocolate chips because I always have them in my pantry. You can use a variation of chocolate with the ganache and do half milk chocolate and half semi-sweet chocolate chips.

Be sure to let the hot cream sit over the chocolate for at least 3 minutes. This waiting period lets the cream melt the chocolate while bringing down the temperature of the cream. If you whisk the cream and chocolate while the cream is still really hot (and fresh from the saucepan) it can cause the ganache to break which will result in a gritty texture.

I wouldn’t start making your ganache until a few minutes before your brownies are ready for the ganache. You don’t want your ganache to harden in the bowl while your brownies are still baking or are just out of the oven.

Cosmic brownies on a white parchment paper.

FAQs

When were cosmic brownies invented?

I’m not sure the exact date for when the cosmic brownies came out, but the company behind them, Little Debbie, started in 1960. 


Why is it called a cosmic brownie? 

Cosmic brownies were originally created because of the cosmic bowling trend and are named because of the colored candies on top that look like the night sky.

What makes cosmic brownies so thick?

I’m not sure about the store-bought recipe, but in my recipe we use cornstarch to get that thick texture.

Can you freeze brownies?

Yes! If you are interested in freezing these brownies, here are a few tips. First, I recommend freezing the brownies without the ganache. Dairy-based foods don’t freeze well. When thawed, dairy products can separate, and that would affect the taste, texture and look of the ganache on the brownies. To freeze brownies, cut the brownies into squares and then wrap them in plastic wrap, two times, and then store in a zip top bag. They can be kept in the freezer for up to one month. When you are ready to eat them, pull them out and let them come to room temperature, make the ganache and spread on top of the individual brownie squares, then sprinkle with rainbow chips.

A bite taken out of a cosmic brownie.

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Squares of rainbow chip topped cosmic brownies on a white parchment paper.
Print Review
5 from 4 votes

Cosmic Brownies

These homemade cosmic brownies are ultra rich and fudgy! Dare i say, WAY BETTER than the store bought version.
Prep Time: 15 mins
Cook Time: 25 mins
Total Time: 40 mins
Servings: 24 brownies

Ingredients
 

  • 1 cup granulated sugar
  • 3/4 cup light brown sugar - packed
  • 12 tablespoons unsalted butter - melted
  • 2 large eggs
  • 1 egg yolk
  • 1 teaspoon vanilla extract
  • 1 cup all purpose flour
  • 3/4 cup unsweetened natural cocoa powder
  • 2 teaspoon cornstarch
  • pinch salt
  • rainbow chips

Ganache

  • 8 oz semi-sweet chocolate - chopped OR 1 1/4 cups chocolate chips
  • 1/2 cup heavy cream
  • pinch salt

Instructions
 

Brownies

  • Preheat oven to 350°F. Line a 13×9 with parchment paper, or with foil (then lightly spray with cooking spray if using foil). 
  • In the bowl of a stand mixer fitted with a paddle attachment, or using hand beaters, beat the melted butter, brown sugar, and sugar on medium speed for 2 minutes.  
  • Add the eggs and egg yolk, one at a time, beating well after each addition. Add the vanilla and mix again.
  •  In a small bowl whisk the flour, cocoa, cornstarch, and salt. 
  • Add the dry ingredients to the wet ingredients and mix until just combined. 
  • Spoon the batter into the prepared pan. Using a spatula, level the batter so that its in an even layer. 
  • Bake for 18-24 minutes. (don’t overbake or they will be dry. Mine baked for about 21 minutes).
  • Remove from the oven and let brownies cool in the pan. 
  • While cooling make the ganache. 

Ganache

  • To make ganache, place the chopped chocolate or chocolate chips in a medium sized heat proof bowl. 
  • In a small saucepan over medium heat, warm the heavy cream. Bring to a simmer, once it’s almost boiling remove from heat and pour the heavy cream over the chopped chocolate. Add pinch of salt.
  •  Let the heavy cream sit over the chocolate for 3 minutes before stirring. *see notes
  • After 3 minutes, use a small whisk and slowly begin whisking the cream and chocolate, starting in the center of the bowl and slowly moving towards the edges. 
  • The ganache will get smooth. Once smooth, let the ganache sit for 5 minutes and then pour over the partially cooled brownies and spread using a spatula. 
  • Sprinkle with rainbow chips.
  • Allow ganache to set, about 2-3 hours, or you can place in fridge for 45 minutes to speed up the process. 

Notes

Brownie Tips:
Don’t over bake. The biggest culprit to dry brownies is over-baking them! All ovens vary. The brownies are done when a toothpick comes out with moist crumbs. 
Remove from the oven and let brownies cool in the pan. Note: they don’t need to be fully cooled before spreading the ganache overtop, but the brownies should be on the cooler side.
Be sure to whisk the dry ingredients together in a separate bowl. Since you have the cornstarch in there, you really want to make sure all the dry ingredients are incorporated evenly. This will help when mixing the dry ingredients into the wet ingredients for a more even dispersion of the cornstarch — resulting in a thick consistency across the entire pan.
Ganache Tips:
You can use 1 1/4 cups of chocolate chips OR finely chopped chocolate. I used chocolate chips because I always have them in my pantry. You can use a variation of chocolate with the ganache and do half milk chocolate and half semi-sweet chocolate chips.
Be sure to let the hot cream sit over the chocolate for at least 3 minutes. This waiting period lets the cream melt the chocolate while bringing down the temperature of the cream. If you whisk the cream and chocolate while the cream is still really hot (and fresh from the saucepan) it can cause the ganache to break which will result in a gritty texture.
I wouldn’t start making your ganache until a few minutes before your brownies are ready for the ganache. You don’t want your ganache to harden in the bowl while your brownies are still baking or are just out of the oven.

Nutrition

Calories: 215kcal (11%)Carbohydrates: 26g (9%)Protein: 2g (4%)Fat: 12g (18%)Saturated Fat: 7g (35%)Cholesterol: 46mg (15%)Sodium: 13mg (1%)Potassium: 120mg (3%)Fiber: 2g (8%)Sugar: 19g (21%)Vitamin A: 286IU (6%)Calcium: 24mg (2%)Iron: 1mg (6%)
Course: Dessert
Cuisine: American
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This recipe was originally published on Aug. 26, 2019. It was republished on July 15, 2021, to include additional information and photos.