Let your inner child indulge when you make a batch of these vibrant, chocolatey, nostalgia-inducing Cosmic Brownies! These dense, fudgy brownies are topped with the smoothest chocolate frosting and plenty of rainbow M&M’s that are sure to make you feel like a kid again.

A square piece of a cosmic brownie is placed on a white plate.


Cosmic Brownies

Of all the ways my mom graced my lunchbox as a kid, Cosmic Brownies were always my favorite treat to see in there! There’s just something so lovable about the rainbow chocolate candies scattered across the tops of those fudgy, plastic wrapped brownies. If you had one in your lunchbox, you were officially the kid that all the others envied in the cafeteria.

As an adult, I’d be lying if I said I didn’t sneak a few Cosmic Brownies for myself here and there. Turns out you just never outgrow the craving, I’m afraid! However, I now have access to my grown up kitchen and baking utensils, which means I can master my own Cosmic Brownies recipe that’s (dare I say) even better than the Little Debbie’s original. Trust me, I’ve seriously mastered this copycat recipe through plenty of delicious trial and error!

The best part of a Cosmic Brownie is that they’re dense and fudgy, not light and cakey. While these homemade brownies are a little thicker than what comes in the little plastic wrapper, they still have the signature density and fudge-like consistency that makes them so satisfying. Plus, the chocolate frosting on top is made with just chocolate chips and heavy cream, making it just like the real deal!

The ingredients for cosmic brownies are placed on a white surface.

How to Make Them

These copycat Little Debbie brownies are SO easy to make, and even better than the pantry staple they’re duplicating!

Preheat. Preheat the oven to 350°F.

Cream. In a large bowl, cream together the white sugar, brown sugar, and melted butter until the mixture is smooth and homogenous.

Whisk. Whisk in the eggs and vanilla until the added ingredients are fully incorporated into the mixture.

Fold. Gently fold in the flour, cocoa powder, and baking powder, being careful not to over mix the batter. Continue folding the ingredients together until the dry ingredients are fully incorporated.

Bake. Coat a 9×13 inch baking pan butter and pour the brownie batter into the pan. Bake the brownies for 40 minutes, or until a toothpick can be cleanly removed from the center of the pan.

Make the frosting. Allow the brownies to cool in the pan while you prepare the frosting by heating the chocolate chips and heavy cream in a small bowl in the microwave for 30 seconds.

Frost. Stir the mixture until all the chocolate chips are melted. Spread the chocolate frosting over the brownies evenly and sprinkle the top with mini-M&M’s. 

Chill. Place the brownies in the fridge for 2-3 hours, or until the chocolate frosting has completely set. 

Enjoy! Cut into squares, serve, and enjoy!

A baking dish is filled with frosted cosmic brownies, topped with M&M candies.

Tips and Tricks

  • If you want a warm brownie, I found it easiest to pop one square in the microwave for about 30 seconds, or until heated all the way through.
  • The M&M’s can be replaced with disc-shaped or sphere-shaped rainbow sprinkles. However, original Cosmic Brownies are topped with candy coated chocolate pieces, so sprinkles will make it less like the intended store-bought brownie.
  • It is important to mix the batter slowly, so you do not add too much air to the brownie mix. This will cause the brownies to have a more cake-like texture.

Storage

You can store these brownies for 4-5 days in the fridge. Storing them on the counter will cause the top chocolate layer to soften and become messy.

In the fridge, make sure to keep these brownies in an airtight food storage container, or in the baking dish wrapped tightly with plastic wrap.

A stack of three brownies is presented on a countertop.

Check out more of my favorite homemade brownie recipes!

For more easy dessert ideas, follow us on Instagram and Facebook!

A stack of three brownies is presented on a countertop.

Get the Recipe: Cosmic Brownies

A childhood favorite, Cosmic Brownies are fudge brownies with a layer of thick chocolate icing and decorated with chocolate candies.
No ratings yet

Ingredients

For the Brownies:

  • 1 cup granulated sugar
  • 1 cup light brown sugar
  • 1 cup salted butter, melted
  • 4 large eggs
  • ½ tsp vanilla extract
  • 1 cup all-purpose flour
  • 3/4 cup cocoa powder
  • 1 tsp baking powder

For the Frosting:

  • 1 ¾ cups chocolate chips
  • ½ cup heavy cream
  • ¼ cup mini-M&M’s

Equipment

  • baking pan

Instructions 

  • Preheat the oven to 350 degrees Fahrenheit.
  • In a large bowl, cream together the white sugar, brown sugar, and melted butter until the mixture is smooth and homogenous.
  • Whisk in the eggs and vanilla until the added ingredients are fully incorporated into the mixture.
  • Gently fold in the flour, cocoa powder, and baking powder, being careful not to overmix the batter. Continue folding the ingredients together until the dry ingredients are fully incorporated.
  • Coat a 9×13 inch baking pan butter and pour the brownie batter into the pan. Bake the brownies for 40 minutes, or until a toothpick can be cleanly removed from the center of the pan.
  • Allow the brownies to cool in the pan while you prepare the frosting by heating the chocolate chips and heavy cream in a small bowl in the microwave for 30 seconds.
  • Stir the mixture until all the chocolate chips are melted. Spread the chocolate frosting over the brownies evenly and sprinkle the top with mini-M&M’s.
  • Place the brownies in the fridge for 2-3 hours, or until the chocolate frosting has completely set.
  • Cut into squares, serve, and enjoy!

Notes

You can store these brownies for 4-5 days in the fridge. Storing them on the counter will cause the top chocolate layer to soften and become messy.
If you want a warm brownie, I found it easiest to heat up one square in the microwave for about 30 seconds, or until heated all the way through.
The M&M’s can be replaced with disc-shaped or sphere-shaped rainbow sprinkles.
It is important to mix the batter slowly, so you do not add too much air to the brownie mix. This will cause the brownies to have a more cake-like texture.
Calories: 507kcal, Carbohydrates: 64g, Protein: 6g, Fat: 27g, Saturated Fat: 17g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 6g, Trans Fat: 1g, Cholesterol: 110mg, Sodium: 170mg, Potassium: 186mg, Fiber: 3g, Sugar: 51g, Vitamin A: 757IU, Vitamin C: 1mg, Calcium: 88mg, Iron: 2mg