Homemade Cosmic Brownies

by Haley // July 26, 2026

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These homemade cosmic brownies taste just like the childhood favorite, only better! They have a rich, fudgy brownie base topped with silky chocolate ganache and the signature rainbow candy-coated sprinkles. One bite and you’ll wonder why you ever bought the boxed version.

If you grew up with cosmic brownies in your lunchbox, this recipe is going to bring back all the nostalgia. These homemade brownies have the same chocolatey goodness, chewy texture, and colorful candies you remember, but they’re made with simple pantry ingredients. That means no artificial flavors or preservatives!

I made this version a little chewier than my classic brownie recipe by adding honey and cornstarch, which help create that signature soft, dense bite. Topped with a thick layer of silky chocolate ganache, they’re every bit as fun as the original, but so much better homemade.

Table of Contents

Why You’ll Love This Recipe

Easy to make. No complicated techniques or hard-to-find ingredients. If you can stir brownie batter, you can make these!
Perfect for any occasion. They’re great for birthday parties, bake sales, lunchbox treats, or whenever you’re craving a homemade chocolate dessert.
A thick layer of ganache. The smooth chocolate topping makes every bite extra indulgent and gives these brownies their iconic look.
Make-ahead friendly. These brownies taste even better after they’ve chilled, making them a great dessert to prepare a day in advance.

Ingredient Notes

Small bowls with chocolate chips, sugar, cocoa powder, eggs, candy sprinkles, flour and cream.

Unsalted butter: Melt the butter and let it cool slightly before mixing so it doesn’t scramble the eggs.
Sugars: Using both granulated sugar and brown sugar gives the brownies the perfect balance of sweetness, moisture, and chewiness.
Eggs + egg yolk: The extra yolk adds richness and helps create that dense, fudgy texture.
Honey: A little honey helps make these brownies extra chewy and keeps them soft for days.
All-purpose flour: Spoon the flour into the measuring cup and level it off for the best results.
Unsweetened cocoa powder: Use a good-quality cocoa powder for the richest chocolate flavor.
Cornstarch: This is the secret ingredient for that signature soft, chewy texture found in classic cosmic brownies.
Vanilla extract: Pure vanilla adds warmth and enhances the chocolate flavor.
Salt: Just a pinch balances the sweetness and makes the chocolate taste even richer.
Semi-sweet chocolate: You can use chopped chocolate or chocolate chips.
Heavy cream: Warm cream melts the chocolate into a silky, glossy ganache.
Candy-coated chocolate sprinkles: A must for cosmic brownies! You can usually find them in the baking aisle or order them online if your grocery store doesn’t carry them.

Refer to the recipe card for the full list of ingredients and measurements.

Recipe Variations

Add espresso powder. Stir 1 teaspoon of espresso powder into the dry ingredients to deepen the chocolate flavor without making the brownies taste like coffee.

Mix in chocolate chips. Fold in ½ to 1 cup of semisweet, dark, or milk chocolate chips for even more chocolate in every bite.

Try different candies. Replace the candy-coated chocolate sprinkles with mini M&M’s, rainbow sprinkles, or chopped mini chocolate candies for a fun twist.

Top with flaky sea salt. Sprinkle a little flaky sea salt over the ganache before it sets for a sweet-and-salty finish.

Add chopped nuts. Mix chopped walnuts or pecans into the batter for a little crunch.

How to Make Cosmic Brownies

In a medium bowl, whisk together the flour, cornstarch, cocoa powder, cornstarch and salt. Set aside.
Using a mixer, beat melted butter and sugars on medium-high speed for about 2 minutes until lighter in color. Add eggs, egg yolk, vanilla, and honey, and mix until combined, scraping down the bowl as needed.
Add the dry ingredients to the wet ingredients and mix just until combined (avoid overmixing).
Spread batter evenly in the prepared pan and bake at 350°F for 25 minutes, or until a toothpick comes out with a few crumbs. Cool completely in the pan for about 1 hour.

Mixing ganache in a small bowl and spreading it on brownies.

Heat heavy cream in a microwave-safe bowl for 1 minute. Add chocolate chips and let sit for 3 minutes, then stir until smooth. If needed, microwave at 50% power in 20-second intervals until melted.
Lift brownies from the pan using parchment paper. Spread ganache evenly over the top, add sprinkles, and refrigerate for 2 hours before slicing.

Expert Tips

Measure accurately. A kitchen scale gives the most precise results for baking. If using cups, spoon flour into the measuring cup and level it off instead of packing it in.

Don’t overmix the batter. Mix the dry ingredients in just until combined to keep the brownies soft and chewy.

Choose the right baking pan. For the best results, use a metal pan for these brownies. Glass and ceramic pans heat differently and can lead to longer bake times or a denser texture. Learn more by visiting my Glass vs. Metal Baking Pans post.

For clean cuts. Chill the brownies before slicing and wipe your knife clean between cuts for neat squares.

Cosmic brownies cut into squares and topped with candy sprinkles.

Make Ahead and Storage Tips

Make ahead. These cosmic brownies are a great make-ahead dessert! You can bake them a day or two before serving and store them covered at room temperature or in the refrigerator.

Storage. Store leftovers in an airtight container at room temperature for up to 3 days or in the refrigerator for up to 1 week. Chilling them also helps create that classic chewy texture.

Freeze for later. Freeze brownies in a freezer-safe container for up to 3 months. For the best texture, thaw them in the refrigerator overnight before serving.

Recipe FAQ

Can I double this recipe?

Yes! To make a larger batch, double all of the ingredients and bake the brownies in a 9×13-inch metal pan. Keep an eye on the baking time, as they may need just a few extra minutes to finish baking.

Where to find candy-coated chips?

The candy-coated sprinkles used on classic cosmic brownies can sometimes be tricky to find. If you don’t see them down the baking aisle of your grocery store, Amazon offers some good options. You can also use rainbow sprinkles, mini M&M’s, or any small candy topping.

Why are my brownies not chewy?

Overbaking can make brownies dry instead of chewy. Be sure to bake just until a toothpick comes out with a few moist crumbs, and avoid overmixing the batter.