These homemade cosmic brownies have all the colorful charm of your favorite Little Debbie brownies, but with so much more flavor. If you’ve ever tried your hand at making nostalgic treats like oatmeal creme pies or tender Lofthouse cookies, you know what a difference “from-scratch” can make!
This homemade version is worth the short time it takes to make them yourself. When I developed this recipe, I adapted my popular fudgy brownie recipe to use as the base layer, then topped it off with a thin layer of decadent chocolate ganache. A finishing sprinkle of rainbow chips on top is what completes the iconic look of cosmic brownies and adds a sweet crunch to each one. Once you make these, you’ll never want to go back to the boxed kind!
Table of Contents
Key Ingredients
These are the main ingredients needed to make the best cosmic brownies! You can find the full list of ingredients and measurements in the recipe card below.
Bittersweet chocolate — adding melted chocolate to the brownie batter alongside the cocoa ensures a decadent flavor and deliciously fudgy consistency. You can use any kind of bittersweet chocolate bar you like. If you don’t have a bar of chocolate, you can use real chocolate chips instead. I recommend avoiding anything labeled as “morsels,” though, as they contain more setting agents and don’t melt as smoothly.
Unsweetened cocoa powder — I used natural cocoa powder since this is combined with the bittersweet chocolate. Dutch-processed cocoa will certainly work in this recipe if you prefer an intense chocolate flavor in your homemade brownies! In testing, the lighter flavor of the natural cocoa powder still produced a rich brownie, so I stuck with this more common cocoa powder type.
Granulated sugar and light brown sugar — plain white sugar and brown sugar combine to sweeten the brownies and help produce their chewy texture. Only have white sugar on hand? Here’s how to make brown sugar with it!
Large eggs and egg yolk — adding an extra egg yolk increases the fat content, giving our brownies the perfect amount of chew. Separate the egg while it’s still cold from the fridge to prevent the yolk from breaking, then let it come to room temperature for easier mixing.
All-purpose flour and cornstarch — mixing starch into plain flour is a simple way to make a brownie a bit softer and chewier! Just like with my funfetti cookies, this simple addition to the batter will keep the brownies soft and less dense.
Semisweet chocolate chips — I love the intense but slightly sweet flavor semisweet chocolate brings to these bars. Mixed with hot heavy cream, it forms the luscious chocolate frosting. Feel free to swap in milk chocolate for a sweeter ganache or bittersweet chocolate for a darker one.
Rainbow candy-coated chocolate chips — each of these colorful treats is like a slightly softer-shelled mini M&M, adding a pretty pop of color for the iconic cosmic brownie look.
Where Do I Find Candy Coated Chocolate Chips?
You can usually find candy-coated chocolate chips online or in the cake decorating aisle of well-stocked grocery stores, baking shops, or craft stores. I used Wilton’s Rainbow Chip Crunch for that original cosmic brownie look—they’re sometimes labeled as “confetti chips” or “cosmic sprinkles.” If you’re having trouble finding them, don’t worry! You can use mini M&Ms or a mix of regular mini chocolate chips and rainbow sprinkles.
Pro Tips For Making The Best Cosmic Brownies
Weigh the ingredients. Dry ingredients can settle or be packed easily into measuring scoops, causing volume measurements to vary pretty widely. Using a kitchen scale is the best way to ensure consistency—plus you don’t have to dirty as many dishes!
For the fudgiest brownies, don’t overbake them. Ideally, there should be a few moist crumbs stuck to your toothpick tester. If you really love a denser, fudgy brownie, you can underbake the brownies by 3 to 5 minutes, or until the toothpick comes out with a small amount of fudgy batter on it.
Let the frosting set slightly before adding the sprinkles. Adding the candy chips on top of the hot ganache can cause them to “bloom,” giving them a hazy appearance. Don’t rush the process if you want professional-looking results!
How To Make Cosmic Brownies
1. Start by preheating your oven to 350°F. Lightly butter or spray an 8×8-inch pan, then line it with a parchment paper sling to lift the brownies out easily. In a small saucepan over medium-low heat, melt the butter and chopped chocolate together, stirring now and then until it’s nice and smooth. Once melted, pour it into a large bowl.
2. Whisk in the cocoa powder, granulated sugar, brown sugar, and vanilla extract until the mixture is glossy and well combined. Then, add the eggs and extra yolk one at a time, giving it a good whisk between each addition.
3. Next, sprinkle in the flour, cornstarch, and salt. Use a spatula to gently fold everything together until there are no streaks of the dry ingredients left.
4. Pour the batter into your prepared pan and smooth it out in an even layer using an offset spatula or the back of a spoon. Pop the pan in the oven and bake for about 30 minutes. You’re looking for set edges and a center that still has a few moist crumbs when tested with a toothpick. Let the brownies cool completely in the pan before frosting.
5. To make the chocolate ganache, place the chocolate chips in a medium heatproof bowl. Heat the cream in a small saucepan until it’s steaming but not boiling—just a minute or two. Pour the hot cream over the chocolate chips and let it sit for 5 minutes to melt the chocolate. Stir the mixture until it’s silky smooth.
6. Pour the frosting over the cooled brownies and spread it out evenly. Chill the pan for about 20 minutes so the frosting can begin to set. Sprinkle the candy-coated chips over the top. Pop it back in the fridge for another 10 minutes to finish setting before slicing into squares or rectangles.
Cosmic Brownie Recipe
Equipment
- 8×8 inch pan
- Whisk
- Microwave safe bowl
- Small saucepan
Ingredients
For the Brownies:
- ¾ cup unsalted butter cubed (170g)
- 4 ounces chopped chocolate bittersweet (113g)
- 1 cup granulated sugar (200g)
- ⅓ cup packed light brown sugar (74g)
- ¼ cup unsweetened cocoa powder (25g)
- 1 teaspoon vanilla extract
- 2 large eggs room temperature
- 1 large egg yolk room temperature
- ¾ cup all-purpose flour (90g)
- 1 tablespoon cornstarch
- ¾ teaspoon salt
For the Frosting:
- ½ cup semisweet chocolate chips (90g)
- ⅓ cup heavy cream (80ml)
- 1 tablespoon rainbow candy-coated chips
Instructions
For the Brownies:
- Preheat the oven to 350°F. Lightly grease an 8×8-inch baking pan with butter or baking spray and line it with parchment paper.
- In a small saucepan, combine the butter and chopped chocolate. Place over medium-low heat and cook, stirring occasionally, until both are fully melted. Transfer the mixture to a large mixing bowl.
- Add the granulated sugar, brown sugar, cocoa powder, and vanilla and whisk vigorously until smooth. Add the eggs and egg yolk one at a time, whisking until each one is combined before adding the next.
- Add the flour, cornstarch, and salt and gently fold the dry ingredients into the chocolate mixture using a silicon spatula until no dry streaks remain. Transfer the batter to the prepared pan and smooth it into an even layer.
- Bake for 35 to 40 minutes or until the edges are set and a toothpick inserted in the center comes out with a few moist crumbs. Let the brownie layer cool completely in the pan.
For the Frosting:
- Place chocolate chips in a medium heatproof bowl and set aside.
- Heat the cream in a small saucepan over medium-low heat until very steamy, 1 to 2 minutes. (Do not boil.) Pour the hot cream over the chocolate chips, and set aside for 5 minutes for the chocolate to melt.
- Stir the chocolate and cream together until fully combined and smooth. If a few pieces of chocolate remain, microwave at 50% power for 10 seconds at a time, then stir until smooth.
- Pour the frosting over the cooled brownies and spread it into an even layer. Refrigerate for 20 minutes or until frosting is mostly set but not hard on top. Sprinkle the candy-coated chips on top. Chill for another 10 minutes before slicing.
Notes
- Use the parchment to lift the brownie slab out of the pan for easier slicing. This will help cut even, clean slices, and you won’t risk damaging your pan with a sharp blade.
Nutrition
Achieving The Iconic Look Of Cosmic Brownies
To create that instantly recognizable cosmic brownie from childhood, start by chilling the brownies in the fridge until firm—this makes for cleaner, sharper edges. Cut the cooled brownie slab in half lengthwise, then slice each half crosswise into four equal pieces to make 8 rectangles. (Use a sharp knife warmed under hot water and dried to slice, wiping the blade down after each cut.)
To mimic the original even further, use a skewer or toothpick to gently press a line down the center of each piece.
How To Store
Cosmic brownies can be stored at room temperature if you plan to enjoy them within a couple of days. Keep them in an airtight container to prevent them from drying out.
For ultra-fudgy and chewy brownies, stash them in the fridge! The cooler temperature and high humidity firm up the texture and make them even more decadent. They should keep well for up to a week.
Frequently Asked Questions
Absolutely! Cosmic brownies freeze beautifully. Just wrap each piece tightly in plastic wrap (but without squishing it) and pop them in a freezer-safe bag or container. They’ll keep for up to 2 months—perfect for chocolate cravings on demand. Let them thaw in the fridge or at room temperature when you’re ready to enjoy.
Sure! If you want to use a 9×13 pan, double the recipe and check the doneness with a toothpick. They may need a few more minutes to bake thoroughly.
If you’ve tried this Cosmic Brownie recipe, then don’t forget to rate it and let me know how you got on in the comments below. I love hearing from you!
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