This Cosmic Brownies Recipe starts with fudge brownies, topped with rich chocolate frosting and rainbow candy pieces. It’s a nostalgic take on your favorite childhood treat!
author’s note
Homemade Nostalgia in Every Bite!
I’ve always had a soft spot for Cosmic Brownies. You know the ones with the super fudgy base, shiny frosting, and colorful rainbow candies on top. They were one of my absolute favorite lunchbox treats growing up (along with Rice Krispie Treats). So naturally, I had to recreate a homemade version that brings back all the same flavors but with better ingredients and even more chocolate flavor.
These brownies are rich and dense just like the classic. They’re made from scratch with real chocolate, a smooth ganache topping, and your choice of rainbow chips or mini M&M’s. They freeze well, slice cleanly, and always stand out at bake sales or birthday parties.
Ingredients
- Semi-Sweet Chocolate Chips: Provide the main chocolate flavor.
- Butter: Adds moisture and richness to the cosmic brownies.
- Sugar: Sweetens and improves texture.
- Vanilla Extract: Enhances chocolate flavor.
- Eggs: Bind ingredients and give structure.
- Dutch Process Cocoa Powder: Intensifies chocolate flavor and color.
- Cornstarch: Makes this cosmic brownies recipe tender.
- Heavy Cream: Gives richness and spreadability to the cosmic brownies.
- Toppings (Rainbow chips, M&M’s, or sprinkles): For decoration and texture.
How To Make Cosmic Brownies Recipe
- Melt butter and chocolate chips together until smooth.
- Whisk in sugars, eggs, and vanilla, then stir in cocoa, flour, cornstarch, and salt.
- Bake in a lined 8×8 pan at 350°F for 30–35 minutes. Let cool completely.
- Make frosting by pouring warm cream over chocolate chips and stirring until smooth.
- Frost and top brownies with rainbow chips or mini M&M’s, chill to set, then slice and enjoy.
Storage
- Room Temperature: In an airtight container for 3 days.
- Fridge: Tightly covered for 1 week; watch for hardening.
- Freezing Cosmic Brownies: Wrap each brownie individually and freeze for up to 3 months. Thaw at room temperature. Expect slight texture changes after thawing.
More Delicious Dessert Recipes:
Cosmic Brownies
Bringing back your favorite childhood treat! Cosmic brownies are a fudgy chocolate brownie with chocolate frosting and rainbow candy sprinkles on top. These Little Debbie copycats are amazing!
Equipment
- 9 x 13-inch baking pan metal
Ingredients
- 18 ounces semi-sweet chocolate chips about 3 completely full cups or 1 and 1/2 (12-ounce) bags; I don’t recommend a different type of chocolate.
- 9 tablespoons unsalted butter cut into cubes
- 1 cup + 2 tablespoons granulated sugar
- 1/2 tablespoon vanilla extract
- 4 large eggs
- 1 large egg yolk
- 6 tablespoons Dutch process cocoa powder Hershey’s dark cocoa powder is dutch process
- 1/2 cup cornstarch
- 3/4 teaspoon salt
- 1-1/2 cups chocolate chips milk, semi-sweet, or dark, whatever you prefer; I like milk best
For the frosting
- 1-1/2 cups semi-sweet chocolate chips
- 1/2 cup heavy cream
- Wilton rainbow chip crunch or mini M&M’s (or sprinkles or mini chocolate chips)
Instructions
- Line a light-colored metal 9×13 pan with parchment paper, leaving an overhang to easily remove bars. Don’t skip this step. Preheat oven to 350°F.
- In a very large microwave-safe bowl, combine the semi-sweet chocolate chips and cubes of butter. Microwave in bursts of 15 seconds, stirring between each burst, until completely melted and smooth. Don’t microwave too long at risk of burning chocolate. Remove from microwave and immediately stir in the sugar. Add the vanilla and 1 egg. Stir until completely incorporated. Add the remaining eggs and egg yolk, one at a time, stirring with a wooden spoon after each addition is completely integrated. It’s thick, but avoid hand/stand mixers as these will beat in too much air.
- In a separate bowl, stir together the cocoa powder, cornstarch, and salt. Add to the brownies along with the 1 and 1/2 cups chocolate chips. Stir until smooth. Transfer to prepared baking pan.
- Bake for 27–33 minutes, watching very carefully near the end. As soon as a toothpick comes out with moist crumbs (make sure it doesn’t hit a melted chocolate chip!) these brownies are done. This is almost always 29–30 minutes in my oven (calibrated). Differences will occur based on individual ovens, humidity, etc. Remove and allow brownies to fully cool at room temperature before topping.
- Add chocolate chips to a large, heat-safe bowl. Place the cream in a small, microwave-safe bowl and microwave on high for 1 minute. Pour over the chocolate chips. Cover bowl with the bottom of a cookie sheet or pan lid (something to keep heat in). Let stand for 4 minutes before stirring until smooth. (If chocolate won’t melt completely, place in microwave for 15 seconds and stir again). Once smooth, pour over the completely cooled brownies and smooth until even. Sprinkle bars evenly with the rainbow chips, sprinkles, or mini M&M’s.
- Place in the fridge, covered, for 1–2 hours, or until the frosting is completely set. To cut: remove brownies from pan using parchment-paper overhang. Cut with a sharp knife. For clean cuts, run knife under hot water, dry, and make a cut. Repeat until all bars are cut out. Return leftovers to an airtight container in the fridge. Brownies are best served chilled.
Final step! Please let us know how it was by leaving a review.
Recipe Notes
Gluten free: brownies are naturally gluten free—confirm with all packaging that products are processed in gluten-free environment. Replace rainbow crunch sprinkles with miniature chocolate chips for gluten free.
Storage: Store Cosmic Brownies in an airtight container at room temperature for 3 days or in the fridge for 1 week (watch for hardening). To freeze, wrap each brownie individually and freeze for up to 3 months. Thaw at room temperature.
Nutrition
Serving: 1serving | Calories: 340kcal | Carbohydrates: 39.3g | Protein: 3.6g | Fat: 19.7g | Cholesterol: 20.6mg | Sodium: 60.3mg | Fiber: 1g | Sugar: 34.6g
Nutrition information is automatically calculated, so should only be used as an approximation.
Cosmic Brownies Recipe FAQ
What if I can’t find rainbow chip sprinkles?
Mini M&M’s, chopped candy-coated chocolate, or colorful sprinkles work great.
Can I double the recipe?
Yes! Bake in a 9×13 pan and add a few more minutes to the bake time.
Do I need to use Dutch-process cocoa?
It gives a deeper color and richer flavor, but regular unsweetened cocoa will still work.
I have a student who found out that I love these Little Debbie’s brownies and bought me a whole box at both Christmas and Valentine’s Day. I don’t know if he loves me or hates me! lol
These bring my back to my childhood. I cannot get enough.
I loved getting these in my lunch as a kid. Can’t wait to make them with my girls! I’m positive they are going to love them!
These were one of my favorite childhood treats!! So fun to recreate at home!
My kids were really happy with these brownies! Such a fun treat!
Oh my gosh — I loved these when I was little. I can’t believe you even found the sprinkles!!!
Hahaha right? They are the best! Thanks!