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These cosmic brownie cookies are soft, fudgy, and packed with nostalgic rainbow chips, just like the classic treat we all grew up loving. They start with a simple chocolate cake mix, so they come together fast and bake into thick, tender cookies with that signature cosmic chocolate flavor. If you love easy chocolate cake mix cookies, this recipe gives you that same brownie‑like richness with a smooth layer of chocolate frosting on top.

These frosted chocolate cookies are fun, colorful, and perfect for parties or anytime you want a playful, retro dessert. The rainbow chips add the best pop of crunch and color, making these cosmic chocolate cookies a guaranteed hit.

More fun treats? Hocus Pocus Cosmic Brownie Bites, Cosmic Brownies, Easy Mississippi Mud Oreo Brownies and these fun Chocolate Cake Cheesecake Truffles!

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What Are Cosmic Brownie Cookies?

These cosmic brownie cookies are made with simple ingredients, but the rich fudge flavor and crunchy rainbow candy sprinkles make them truly out of this world. Inspired by Little Debbie’s Cosmic Brownies, these cosmic chocolate cookies take that nostalgic classic and give it a fun, retro twist.

With creamy chocolate frosting and a smooth, chocolate‑chip‑loaded cookie base, every bite tastes like a cosmic treat. And because they’re cake mix cosmic cookies, they require almost no baking skills — just mix, bake, frost, and enjoy a batch of colorful, frosted chocolate cookies in minutes.

If you’re into soft, fudgy, bakery‑style cookies, you’ll love these Chocolate Chip Cookies, these Soft Sugar Cookies, and these Cinnamon Churro Cookies — they all share that thick, tender texture that makes cosmic brownie cookies so irresistible.

Why You’ll Love These Cosmic Brownie Cookies

- Nostalgic cosmic brownie flavor Soft, fudgy chocolate cookies topped with frosting and rainbow chips for that classic cosmic vibe.
- Made with cake mix No fuss, no complicated steps. Just mix, scoop, bake, and frost.
- Thick, soft, and fudgy The texture lands right between a brownie and a cookie, with a smooth chocolate base that stays tender.
- Fun and colorful Rainbow chips make these rainbow chip cookies instantly eye‑catching and perfect for parties, bake sales, or retro‑themed treats.
- Kid‑friendly and crowd‑pleasing Everyone loves a cosmic throwback, and these cookies disappear fast.
- Perfect for beginners If you can stir a bowl, you can make these. They’re practically foolproof.

So grab your mixing bowl and get ready to bring a taste of the universe to your kitchen with this simple recipe for making Cosmic Chocolate Cookies.

The 6 Ingredients You Need for Cosmic Cookie Recipe Using Cake Mix

Cosmic Cookie Cake Mix Recipe

1 box dark chocolate cake mix or whatever chocolate cake mix you like
vegetable oil or melted butter, cooled – make sure not to overmeasure the oil/butter
eggs
semi-sweet chocolate chips or dark chocolate chips
2 tubs of dark chocolate frosting, depending how much frosting you want, you may get by with 1 tub of frosting or make this homemade chocolate frosting
rainbow candy-coated chocolate chips or you can also use or mini m&m’s

Instructions How to Make Super Easy Cosmic Chocolate Brownie Cookies!

Oven preheating will happen in Instruction #4, so cookies can chill for 10-15 minutes.
In a large mixing bowl, stir or whisk together the cake mix, oil, and eggs together and mix together until just incorporated.
Add the chocolate chips & candies and mix well.
Preheat your oven to 350 degrees F and line a cookie sheet with parchment paper or a silicone baking sheet. Alternatively, you could spray it with nonstick cooking spray.
Use a medium cookie scoop to scoop even-sized cookie dough balls or spoon tablespoons of the cookie dough and place in fridge for 10-15 minutes while your oven preheats.
When you’re ready to bake, place cookies 2 inches apart on the parchment-lined baking sheets.
Bake cookies for 8-10 minutes.
Transfer to a baking rack and let cookies cool.

Frosting & Decorating Chocolate Cake Mix Cookies

Once cookies are cooled, frost the cookies with an offset spatula or transfer frosting to a pastry/piping bag and pipe onto cookies.
Sprinkle rainbow chocolate chips or mini m&m’s on top of cookies and let the frosting firm up.

Variations for Cosmic Chocolate Cookies

Double Chocolate Cosmic Cookies – Add mini chocolate chips to the dough for extra fudgy richness.
Peanut Butter Cosmic Cookies – Swirl a spoonful of peanut butter into the frosting or add peanut butter chips.
Mint Cosmic Cookies – Add a drop of peppermint extract to the frosting for a cool, cosmic twist.
Birthday Cosmic Cookies – Swap rainbow chips for pastel sprinkles for a funfetti vibe.
Salted Cosmic Cookies – Add a tiny pinch of flaky sea salt on top of the frosting for a sweet‑salty finish.

Tips for the Best Cosmic Brownie Cookies

Don’t overbake. These cookies should look slightly soft in the center when you pull them out. They firm up as they cool.
Chill the dough if needed. If your dough feels sticky, a quick 10–15 minute chill helps create thicker, puffier cookies.
Use a cookie scoop. Ensures even baking and consistent thickness.
Frost while slightly warm. The frosting melts just enough to create that smooth cosmic brownie finish.
Press on the rainbow chips gently. This keeps them from falling off once the frosting sets.

How to Store Cosmic Chocolate Cookies

Room Temperature: Store in an airtight container for 3–4 days. The frosting stays soft and creamy.
Refrigerator: Store up to 1 week. Let cookies come to room temp before serving for the best texture.

How to Freeze Cosmic Chocolate Cookies

Freeze Unfrosted Cookies: Bake, cool completely, then freeze in a single layer. Transfer to a freezer bag. Freeze up to 2 months.
Freeze Frosted Cookies: Freeze on a baking sheet until frosting is firm, then store in layers separated by parchment.
Freeze Dough Balls: Scoop dough, freeze solid, then store in a freezer bag. Bake from frozen, adding 1–2 minutes.

FAQs for Cosmic Chocolate Cookies

Can I use a different cake mix?

Yes. Devil’s food or dark chocolate cake mix gives the richest cosmic brownie flavor.

Can I make these without frosting?

You can, but the frosting is what gives these cosmic cookies their signature look and taste.

Can I use regular sprinkles instead of rainbow chips?

Yes, but rainbow chips give the true cosmic brownie vibe.

Why are my cookies flat?

Your dough may have been too warm. Chill 10–15 minutes before baking.

Why are my cookies dry?

They were likely overbaked. Pull them out when the edges are set but the centers still look soft.

Can I make these ahead?

Yes. Bake the cookies, store unfrosted, and frost the day you plan to serve.

Healthy Swaps

Use Greek yogurt instead of part of the oil for a lighter cookie.
Use sugar‑free rainbow chips or sprinkles.
Use light whipped frosting instead of full buttercream.

Serving Ideas

Serve chilled for a fudgier brownie‑like texture.
Warm slightly for a melty, gooey center.
Add a scoop of ice cream and make cosmic cookie sundaes.
Cut cookies in half and use as ice cream sandwich “buns.”

Make‑Ahead Notes

Bake cookies 24–48 hours ahead and store unfrosted.
Frost right before serving for the freshest look.
Dough can be made up to 3 days ahead and chilled.

This easy Cosmic Brownie Cookies recipe makes it simple to whip up soft, fudgy cosmic cake mix cookies that everyone will love. Who can resist a chocolate‑loaded cookie with creamy frosting and rainbow chips? Kids and adults alike will enjoy every cosmic bite — a fun, whimsical treat that always disappears fast.

Time to make your own heavenly Cosmic Chocolate Cookies for some fun party treats for birthdays, St. Patrick’s Day, Halloween and whenever you want rainbow chips full of color to celebrate!

Want more quick ideas and dessert inspo? Follow on Pinterest, Instagram or Facebook for recipe updates, baking tips, and lots of sweet inspir

More Fun Treats!

Easy Cosmic Chocolate Cookies

Kim Lange

If you’re looking for a creative twist on the classic chocolate cookie, these Super Easy Cosmic Chocolate Cookies loaded with sprinkles of rainbow color are the perfect way to spark cosmic joy without all the fuss.

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Print Recipe Pin Recipe

Prep Time 10

Cook Time 1 50

chill time 10

Course Dessert

Servings Servings

Calories

Ingredients

1 box dark chocolate cake mix or whatever chocolate cake mix you like
½ cup vegetable oil or melted butter, cooled
2 large eggs
1 cup semi-sweet chocolate chips
2 tubs dark chocolate frosting 2 tubs of dark chocolate frosting, depending how much frosting you want, you may get by with 1 tub of frosting or make this homemade chocolate frosting
Rainbow chocolate chips or mini m&m’s

US Customary - Metric

Instructions

Oven preheating will happen in Instruction #4, so cookies can chill for 10-15 minutes.
In a large mixing bowl, combine the cake mix, oil, and eggs together and mix together until just incorporated.
Add the chocolate chips & candies and mix well.
Preheat your oven to 350 degrees F and line a cookie sheet with parchment paper or a silicone baking sheet. Alternatively, you could spray it with nonstick cooking spray.
Use a medium cookie scoop to scoop even-sized cookie dough balls and place in fridge for 10-15 minutes while your oven preheats.
When you’re ready to bake, place cookies 2 inches apart.
Bake cookies for 8-10 minutes.
Transfer to a baking rack and let cookies cool.
Once cookies are cooled, frost the cookies with an offset spatula or transfer frosting to a pastry/piping bag and pipe onto cookies.
Sprinkle rainbow chocolate chips or mini m&m’s on top of cookies and let the frosting firm up.