Cosmic Brownies

If you grew up on Little Debbie Cosmic Brownies, this homemade version will hit you with the perfect wave of nostalgia—but better. Rich, chewy, and topped with a silky ganache and colorful candy-coated sprinkles. These brownies back up in less than 30 minutes and without a stand mixer!

 

Whether you’re baking for a birthday party, reliving childhood treats, or just in the mood for a seriously chocolatey dessert, cosmic brownies deliver. They’re incredibly easy to make and require only simple ingredients. The texture is dense and fudgy with that signature glossy top, and the ganache layer takes them totally over the top.

Cosmic brownies are a copycat version of the iconic lunchbox treat of the Little Debbie brownies. They’re known for their dense, fudgy base and a thick layer of glossy chocolate ganache, finished with rainbow candy-coated chips or sprinkles.

This homemade version keeps all the fun while improving the taste and texture—richer chocolate flavor, better quality ingredients, and no preservatives. And you know I love my copycat Little Debbie treats around here. Like these homemade oatmeal cream pies, and these chocolate fudge rounds cookies.

These brownies have something for everyone: kids love the bright sprinkles, and adults love the deep cocoa flavor and chewy bite. They slice neatly, travel well, and make a fun bake for potlucks, lunchboxes, or midnight cravings. While the store-bought kind has that unmistakable childhood flavor, homemade cosmic brownies give you control over the sweetness and ingredients. Plus, they’re way more decadent. You can also get creative with the toppings or add flavor twists like espresso powder or sea salt.

The key to cosmic brownies’ charm is the rich ganache topping. Made from melted chocolate and cream, it adds a smooth, truffle-like finish that firms up beautifully in the fridge. And of course, the iconic rainbow chips (or colorful sprinkles) give that playful, nostalgic touch.

Why This Recipe Works

• Fudgy Base: Melted butter and cocoa powder create a rich and dense brownie layer.
• Rich Chocolate Ganache Topping: A simple chocolate-and-cream combo sets up perfectly in the fridge and is spread over the brownies.
• Copycat Cosmic Brownies – Just like the Little Debbie version but way, way better!
• Kid-Friendly and Freezer-Friendly: Great to make ahead and a hit with all ages.

Ingredients Needed

• Unsalted butter – You can use salted butter, just reduce or omit added salt.
• Granulated sugar 
• Brown sugar – If you don’t have any, then make your own homemade brown sugar.
• Large eggs – Use room temperature eggs. Place in a bowl of warm water for 10 minutes before using. For my full tutorial, read how to bring eggs to room temperature fast.
• Vanilla extract 
• Unsweetened cocoa powder – Use Dutch-processed for a darker, richer chocolate taste.
• All-purpose flour  – For best results, weigh your flour using a kitchen scale. Or if using a measuring cup, stir the flour first.  Then spoon the flour into the measuring cup and level it off. Do not pack it down. Too much flour = cakey, dry brownies so measure carefully!
• Salt 
• Heavy cream 
• Semi-sweet chocolate – You can use semi-sweet chocolate chips or chopped semisweet chocolate bar.
• Rainbow candy-coated chips or rainbow sprinkles – For the signature cosmic brownie finish.

How to Make Cosmic Brownies

Prep oven and pan. Position a rack in the center of your oven and preheat the oven to 350°C (180°C). Line an 8×8” pan with parchment paper, or grease with non-stick cooking spray. See note below about using a metal or glass pan.

Combine dry ingredients. In a small mixing bowl, whisk together the flour, salt, and baking powder. Set aside. 

Combine wet ingredients. In a large mixing bowl, whisk together the granulated white sugar, eggs, brown sugar, oil, and vanilla. 

Combine butter and chocolate. In a small saucepan on the stove, over low heat, melt and stir together the butter and chopped chocolate.

Stir frequently to keep the chocolate from burning. Remove from the heat and stir in the cocoa powder, whisking to combine.

Add chocolate mixture to sugar mixture. Whisk the chocolate/butter mixture into the sugar/egg mixture until smooth and combined.

Add dry ingredients. Stir, using a spatula (or wooden spoon) in the dry ingredients until just combined. 

Bake brownies. Spread the brownie batter into the prepared pan. Bake for 22 to 27 minutes until a toothpick inserted in the center comes out with a few moist crumbs clinging to it. Transfer the pan to a wire rack to cool completely before cutting into bars and serving.

Make ganache. In a microwave safe bowl heat heavy cream until very hot (steaming not boiling). This can vary depending on microwave but 30 seconds to 1 minute). Then add chocolate chips. Do not stir for 3 minutes. Then stir smooth.

Spread the chocolate icing over the cooled brownies and sprinkle on the rainbow chips.

Recipe Tips

• Don’t overbake! Brownies continue to cook as they cool so it’s best to take them out when they look slightly underdone. 
• Line the pan with parchment for easy lifting and clean edges.
• Chill the brownies before slicing for the neatest cuts. I like to slice with a clean, sharp chef’s knife and wipe off in between each cut. You can also use a plastic knife for clean cuts.
• For a flavor twist, add a teaspoon of espresso powder to the batter.

Recipe Storage Instructions

• Room Temperature: Store in an airtight container for up to 3 days.
• Fridge: Keeps well for up to a week—just let them come to room temp before serving for the best texture.
• Freezer: Slice and freeze brownies individually. Wrap in plastic wrap and store in a zip-top bag for up to 3 months. Thaw in the fridge or at room temperature.

Recipe FAQ

More Recipes To Try

If you are craving more brownies, then be sure to try my Buckeye Brownies which have a thick peanut butter layer just like Buckeye candy!

Or try these brown butter brownies. The browned butter gives the brownies them a bit of extra nuttiness and chewiness.