By: Jill Mills Updated: Jun 23, 2025

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With dense, chewy brownies topped with a rich ganache frosting and rainbow candy-coated chocolate chips, these Cosmic Brownies are a nostalgic treat. Easy to make & better than the store-bought version!

A stack of three cosmic brownies, one with a bite missing

It seems like every kid since the 90s has found Little Debbie Cosmic Brownies in their lunch box. I know many 90s kids who are now adults that still sneak one every now and again. I made this recipe for the inner 90s-kid in all of us. It’s similar to the original treat but with a much better flavor – these actually taste like chocolate! They’re simple to make too. I recommend making a double batch to freeze some!

Why These Cosmic Brownies Are A Must-Make

Here are a few reasons why this copycat recipe has become a regular on my baking rotation.

Better than store-bought. This copycat recipe keeps all the best elements of the original cosmic brownies – the dense, chewy texture, rich frosting, and candy-coated chocolate chips on top. What it doesn’t have is a ton of preservatives or added ingredients.
A nostalgic treat. Kids today love these because they’re colorful and fun. And anyone who grew up in the 90s loves these because they remind them of their childhood. Basically, they’re a win-win no matter who enjoys them.
Super easy to make. This cosmic brownies recipe is made with a handful of basic pantry ingredients in just a few steps. A few bowls and a whisk are really all you need! I find the hardest part is waiting for the frosting to set before slicing and enjoy.

Overhead view of ingredients needed to make homemade cosmic brownies

Recipe Ingredients

These brownies are made with pretty basic ingredients, plus a few extras to help achieve that perfect texture. Scroll down to the recipe card below for the exact measurements.

Brownie Ingredients:

Butter – Be sure to measure the butter accurately, as the extra 2 tablespoons makes a difference. I recommend unsalted butter here.
Sugar – These brownies are sweetened with granulated sugar plus a bit of light brown sugar. The light brown sugar helps add extra moisture to the brownies.
Cocoa powder – For the rich chocolate flavor.
Vanilla extract
Eggs – The extra yolk is important for achieving that perfectly chewy texture.
Corn syrup & cornstarch – These are my two secret ingredients for achieving that dense, chewy cosmic brownie texture.
All-purpose flour
Salt

Frosting Ingredients:

Heavy cream – Makes the frosting spreadable.
Semi-sweet chocolate chips – Use a quality brand, such as Ghirardelli or Hershey for the best flavor.

Topping:

Candy-coated chocolate chips – The quintessential cosmic brownie topping! These are usually found in the baking aisle or can easily be ordered online. If candy-coated chocolate chips aren’t available, try using rainbow sprinkles or chopped chocolate candies.

How To Make Copycat Cosmic Brownies

This copycat recipe is so easy to make with just a bowl and a whisk. The printable instructions are in the recipe card below.

Prep. Preheat the oven to 325F. Grease the baking dish and line it with parchment paper.
Make the batter. Whisk the melted butter and sugars until smooth. Add the cocoa powder, vanilla, eggs, and corn syrup and mix until the batter is fully combined with no lumps. Gradually fold in the flour, cornstarch, and salt until the batter is smooth.

Bake. Transfer the batter to the baking dish, spreading it evenly with a spatula to smooth the top. Bake for 25-28 minutes, until the edges are set and the center is still fudgy. Cool completely before frosting.

Chocolate chips and heavy cream in a bowl

Spreading chocolate frosting on brownies

Make the frosting. Heat the heavy cream over medium heat until it just begins to simmer. Pour over the chocolate chips. Whisk until the chocolate is fully melted and the frosting is smooth and glossy. Pour over the cooled brownies.
Chill. Press the candy-coated chocolate chips lightly into the frosting. Transfer the brownies to the fridge for at least 30 minutes to allow the frosting to firm up. Slice and enjoy!

Overhead view of homemade cosmic brownies

Tips & Tricks

Here are a few things I’ve found helpful when making these copycat cosmic brownies, as well as a few variation options.

Avoid overbaking. The edges of the brownies should be set but the center should still appear slightly fudgy. A toothpick inserted in the center should come out with a few moist crumbs (but not wet batter).
Cool before frosting. Be sure to let the brownies cool completely in the pan before adding the frosting.
Chill before slicing. The frosting will be very liquid when first added to the brownies but once it chills, it will solidify like the frosting on the store-bought treat. 30 minutes in the fridge is usually plenty of time.
Add-in ideas. Enhance these brownies by folding in extras like chopped nuts, mini marshmallows, or crushed cookies.
Adjust the frosting. Replace semi-sweet chocolate chips in the frosting with milk chocolate or dark chocolate based on your taste preferences.
Get clean, even cuts. Use a sharp knife and clean it between each cut for neat, even brownie squares.

Proper Storage

Room temperature. Homemade cosmic brownies can be stored in an airtight container at room temperature for up to 3 days.
Fridge. For slightly longer storage, keep them in an airtight container in the fridge. They’ll last for up to a week.
Freezer. Once the frosting has set completely, wrap the brownies in plastic wrap then transfer to a ziploc bag. Freeze for up to 3 months. Thaw on the counter.

Cosmic Brownies

Why These Cosmic Brownies Are A Must-Make