These Homemade Cosmic Brownies are just like the original Little Debbie version, only even better. There's more chocolate flavor in these fudgy, rich brownies that get treated with a fudge frosting and sprinkled with candy coated chocolate sprinkles for an out-of-this-world treat.

Looking for fun, colorful dessert ideas? Our Homemade Funfetti Cake and Homemade Rainbow Chip Frosting are reader favorites that you might also enjoy!

Homemade cosmic brownies on a white surface next to some on plates and a glass of milk.


When I was growing up Little Debbie brownies were just regular frosted brownies with walnuts on the top. Still definitely a yummy childhood lunchbox treat, but it wasn't until 1999 when Little Debbie introduced their cosmic brownies with the rainbow colored chocolate pieces on top that they seemed to gain a cult following!

While some folks might guess that the name comes from their colorful chips giving these galaxy brownies an intergalactic look, the moniker was actually in tribute to the popular cosmic bowling craze of the 90's! Bowling in the dark with black lights making everything glow neon is something I definitely grew up with, and it's what actually inspired the look of these treats!

Other Little Debbie favorites included oatmeal cream pies, star crunch, zebra cakes, Christmas tree cakes, and honey buns.

Rows of brownies with chocolate frosting and rainbow coated chocolate chips sprinkled on top.

Why this Recipe Works

  • Homemade cosmic brownies have a really dense, fudgy brownie layer with a creamy but firm fudgy icing on top, just like the originals.
  • Most other homemade cosmic brownies recipes use a chocolate ganache on top. But the actual cosmic brownies have a chocolate icing that firms up into a fudgy, solid layer. It's basically the same icing I use when I make Bumpy Cake, so I just scaled that back and adjusted a few things to make it work for these brownies.
  • The rainbow coated chocolate pieces add a fun pop of color but also an interesting texture to the top of these brownies.

Ingredient Notes

  • Rainbow coated chocolate chips: I have seen these at many grocery stores (the ones I used are Wilton brand called "rainbow chip crunch" and are by all the other sprinkles) but they are also easy to find at craft stores like Joann's, Michael's, or Hobby Lobby. Or you can always just order them online.
  • Cocoa powder: I made these with good old Hershey's unsweetened cocoa powder.
  • Sugar: The combination of granulated sugar and brown sugar gives a better depth of flavor to the cosmic brownies than using just granulated sugar.
Ingredients for making homemade cosmic brownies in separate bowls on a white surface.

How to Make This Recipe

Start by beating the melted butter with both types of sugar in a large bowl. This can also be done by hand. Add the eggs, egg yolk, and vanilla, then beat again.

Stir in the flour, cocoa powder, cornstarch, and salt by hand just until everything is combined.

Pour and spread into the corners of a 9x13-inch pan lined with a parchment paper sling for easy removal once the brownies have cooled. Bake for 18-22 minutes, just until the brownies are done and a toothpick inserted into them comes out with just a few crumbs on it. You don't want to overbake or the brownies will be dry.

Cool completely before topping with the fudge frosting.

To make the fudge frosting, start by combining the sugar, milk, butter, and cocoa powder in a medium saucepan over medium heat. Cook, stirring frequently until the butter has melted and the mixture comes to a boil. Boil for 3 minutes, then remove from the heat and beat in the powdered sugar and vanilla until smooth.

While the frosting is still hot, pour it over the cooled brownies and tilt the pan to spread the frosting into the corners and create an even layer of fudge icing on top.

Sprinkle with the rainbow coated chips while the frosting is still soft so they can sink in slightly since the fudge frosting sets up fairly quickly.

Let your homemade cosmic brownies sit uncovered until the frosting has cooled completely and had a chance to set up before lifting them out of the pan and slicing into rectangles or squares.

If you want clean edges when slicing these homemade cosmic brownies, I recommend chilling them for a bit first so they are cold. If I'm taking pics and wanting really clean slices, I will even go so far as to rinse the knife under hot water and wipe it with paper towels between each slice. Also, try to do one quick slice, rather than dragging the knife through the brownies, which can cause them to tear and stick to the knife.

Chocolate frosted brownies cut into squares.

Recipe FAQ's

Can I make these with ganache instead of fudge frosting?

You can certainly use a chocolate ganache for your homemade cosmic brownies if you prefer it over making the cooked fudge frosting. I have made them both ways and they turn out good, I just prefer the fudge frosting in terms of taste and being more like the classic cosmic brownies. For a ganache, just heat ½ cup heavy cream in the microwave for 60 seconds until very hot. Pour the hot cream over 1 cup semisweet chocolate chips and ½ cup milk chocolate chips in a bowl with a pinch of salt and let this sit WITHOUT STIRRING for 3 minutes. Once the chocolate has had a chance to melt, whisk or stir until you have a thick, smooth ganache. Pour and spread over the brownies in place of the fudge frosting, then let cool until set.

Why use an egg yolk in place of a whole egg?

The reason for using an egg yolk is that it adds richness and density to the brownies without making them quite as cake-like. It really adds to that chewy, fudge-factor of homemade cosmic brownies.

Recipe Tips

  • Storage: You can keep these brownies on the counter in an airtight container for 4-5 days or in the fridge for about a week.
  • Freezing: These freeze great for 2-3 months. I recommend slicing and separating the brownies, then freezing them on a baking sheet for an hour before transferring to an airtight freezer-safe container for longer term storage. Thaw on the counter for a couple of hours before enjoying.
  • Pan size: You could make these in a smaller pan like a 9x9 for thicker cosmic brownies, but you will need to adjust the baking time to be a little longer, probably more like 26-30 minutes.

More Brownie Recipes

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Let me know what you thought with a comment and rating below. You can also take a picture and tag me on Instagram @houseofnasheats or share it on the Pinterest pin so I can see.

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Homemade Cosmic Brownies

5 from 2 votes
Amy Nash
Prep Time 15 minutes
Cook Time 25 minutes
Cooling Time 2 hours
Total Time 2 hours 40 minutes
Course Dessert
Cuisine American
Servings 24 brownies
These Homemade Cosmic Brownies are just like the original Little Debbie version, only even better. There's more chocolate flavor in these fudgy, rich brownies that get treated with a fudge frosting and sprinkled with candy coated chocolate sprinkles for an out-of-this-world treat.

Ingredients
  

Brownies

  • 1 cup granulated sugar (200g)
  • ¾ cup light brown sugar (150g)
  • ¾ cup salted butter, melted (12 Tablespoons)
  • 2 large eggs
  • 1 egg yolk
  • 2 teaspoons vanilla extract
  • 1 cup all-purpose flour, scooped & leveled (141g)
  • ¾ cup unsweetened cocoa powder
  • 2 teaspoons cornstarch
  • ¼ teaspoon salt

Fudge Frosting & Decorating

  • 1 cup granulated sugar (200g)
  • ½ cup salted butter, cubed
  • ½ cup milk
  • ¼ cup corn syrup
  • cup cocoa powder (6 Tablespoons)
  • 2 ½ cups powdered sugar
  • 2 teaspoons vanilla extract
  • Rainbow coated chocolate chips, for decorating

Instructions
 

Brownies

  • Preheat oven to 350°F. Line a 9x13-inch pan with a parchment paper sling or spray with baking spray.
  • In a large bowl, beat the granulated sugar, brown sugar, and butter together until light, about 2 minutes. Add the eggs, egg yolk, and vanilla, then beat or whisk well.
  • Stir in the flour, cocoa powder, cornstarch, and salt until combined. Pour the batter into the prepared pan, using a spatula to spread it into an even layer.
  • Bake for 18-22 minutes just until done, but do not overbake. Remove and cool in the pan.

Fudge Frosting

  • While the brownies are cooling, prepare the fudge icing by combining the sugar, butter, milk, corn syrup, and cocoa powder in a medium saucepan over medium heat.
  • Cook and stir until the mixture comes to a boil. Boil for 3 minutes, stirring frequently, then remove from the heat and beat in the powdered sugar and vanilla extract until smooth.
  • Immediately pour the hot frosting over the brownies. Tilt the pan while the frosting is still hot to cover the edges. Sprinkle with the rainbow coated chocolate chips while the icing is still soft before it has a chance to set up.
  • Let the brownies cool completely, at least 2-3 hours, before cutting into squares so the frosting can set up completely.

Notes

  • Storage: You can keep these brownies on the counter in an airtight container for 4-5 days or in the fridge for about a week.
  • Freezing: These freeze great for 2-3 months. I recommend slicing and separating the brownies, then freezing them on a baking sheet for an hour before transferring to an airtight freezer-safe container for longer term storage. Thaw on the counter for a couple of hours before enjoying.
  • Rainbow coated chocolate chip options: These sprinkles are pretty easy to find at most craft stores like Jo-Ann Fabric & Crafts, Michaels, or Hobby Lobby in their baking/cake decorating section. Wilton makes the brand that I used called "rainbow chip crunch". I have even seen them at my regular grocery store in the baking aisle, but you can also order online. Or use mini M&Ms (the closest substitute flavor and texture-wise), regular sprinkles, or even chocolate covered sunflower seeds instead.
  • Ganache option: Instead of the pourable fudge frosting, you can heat ½ cup heavy cream in the microwave for 60 seconds until very hot. Pour over 1 cup semisweet chocolate chips and ½ cup milk chocolate chips with a pinch of salt in a bowl and let this sit for 3 minutes without stirring. After 3 minutes, whisk or stir until the chocolate is all melted and smooth. Pour and spread over the brownies in place of the fudge frosting.
  • Pan size: You could make these in a smaller pan like a 9x9 for thicker brownies, but you will need to adjust the baking time to be a little longer, probably more like 26-30 minutes.

Nutrition

Calories: 275kcal | Carbohydrates: 45g | Protein: 2g | Fat: 11g | Saturated Fat: 7g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 3g | Trans Fat: 1g | Cholesterol: 48mg | Sodium: 122mg | Potassium: 91mg | Fiber: 1g | Sugar: 39g | Vitamin A: 334IU | Calcium: 24mg | Iron: 1mg
Tried this recipe? Show me on Instagram!Mention @HouseOfNashEats or tag #houseofnasheats!

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About the author

Hi, I'm Amy

I enjoy exploring the world through food, culture, and travel and sharing the adventure with mostly from-scratch, family friendly recipes that I think of as modern comfort cooking.

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