This Cosmic Brownies Copycat recipe brings back those lunchbox memories with fudgy brownies, silky chocolate frosting, and rainbow chips!
So, you remember those little plastic-wrapped Cosmic Brownies? The ones you’d find in your lunchbox and instantly feel like the coolest kid ever? Yeah, those.
I used to beg my mom to toss them in my lunch. Most of the time, she handed me a homemade oatmeal cookie instead (no hate, but not the same). So, when a friend finally slid me a trade—my PB&J for her Cosmic Brownie—it was like I’d won the lunchbox lottery.
Fast forward a couple of decades, and I had this random craving for them while binge-watching old cartoons with my kid. But, have you tried them as an adult? They’re… fine. But kinda waxy and way sweeter than I remember. So, I set out to recreate them—homemade style.
This Cosmic Brownies Copycat recipe? It’s richer. Fudgier. Real chocolate, real butter, no mystery ingredients. And that ganache? Yeah, it’s next level. Plus, those rainbow chips? They’re not just for looks—they’re fun. Trust me, one bite and you’ll feel like a kid again.
Why You’ll Love This Cosmic Brownies Copycat Recipe?
- Nostalgia Alert: It’s like the classic lunchbox treat—but better.
- Super Fudgy: These brownies are dense and rich, not cakey.
- Easy Ingredients: You’ve probably got everything in your pantry right now.
- Ganache Heaven: The silky chocolate frosting is made from actual chocolate, not mystery goo.
- Party-Perfect: That rainbow topping? Hello, instant crowd-pleaser.
Ingredient Notes:
Let’s talk about the key players here, shall we?
- Butter: Melted, unsalted butter makes these brownies rich and fudgy. Margarine just won’t cut it here.
- Cocoa Powder: Use unsweetened cocoa powder. The better the cocoa, the more chocolatey the brownies. Trust me on this one.
- Granulated + Brown Sugar: The combo makes these sweet and a little caramel-y.
- Corn Syrup: It’s not just for looks! It adds chewiness and keeps the brownies moist.
- Eggs + Extra Yolk: That bonus yolk makes these extra rich. Weird but wonderful.
- Flour + Cornstarch: Cornstarch is my secret weapon for soft, melt-in-your-mouth brownies.
- Heavy Cream + Chocolate Chips: These two make the ganache. And yes, it is as dreamy as it sounds.
- Rainbow Chips: Go classic with Wilton Rainbow Crunch or even mini M&Ms.
Pro Tip: Don’t skip sifting the cocoa powder. It clumps. A lot. And no one wants cocoa lumps in their brownies.
How To Make Cosmic Brownies Copycat?
This is where the magic happens.
Step 1. Preheat & Prep:
First things first—preheat your oven to 350°F (175°C). Line an 8×8-inch metal baking pan with parchment paper or foil (seriously, it makes clean-up so much easier). Lightly spray it with cooking spray too, because nobody likes stuck brownies.
Step 2. Melt the Butter & Mix:
Melt the butter in a microwave-safe bowl—about 90 seconds should do it. Stir in the granulated sugar, brown sugar, and cocoa powder until smooth. If it’s too hot, let it cool for a minute.
Step 3. Add the Wet Ingredients:
Mix in the vanilla extract, eggs, egg yolk, and corn syrup. Stir gently—overmixing here is not your friend. The batter should look thick and glossy.
Step 4. Add the Dry Ingredients:
Sift in the flour, cornstarch, and salt. Fold it all together—just until the dry bits disappear. The batter will be thick (and yes, you’ll be tempted to eat it with a spoon… I get it).
Step 5. Bake the Brownies:
Spread the batter evenly into your prepped pan. Bake for 25 minutes or until the edges are set and the center is just slightly soft. That’s fudgy brownie perfection, my friend.
Step 6. Cool Completely:
Let the brownies cool completely before frosting. I know, the wait is brutal. But trust me, it’s worth it.
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Frosting Time – The Ganache Moment
Step 1. Heat the Cream:
Microwave the heavy cream for about 1 minute—just hot enough to melt the chocolate but not boiling.
Step 2. Melt the Chocolate:
Pour the chocolate chips into the hot cream. Let them sit for 3 minutes (resist the urge to stir—this makes the ganache ultra-smooth).
Step 3. Stir Smooth:
Once rested, stir gently until smooth and glossy. It’s so satisfying.
Step 4. Frost & Decorate:
Pour the ganache over the cooled brownies and spread it evenly. Then, shower them with rainbow chips!
Step 5. Chill Time:
Refrigerate the brownies for 1-2 hours so the frosting sets. It’ll be worth the wait—I promise.
Storage Options:
- Fridge: Store in an airtight container for up to 5 days.
- Freezer: Freeze individual brownies for up to 2 months.
- Room Temp: Okay for a day or two, but they’ll be softer if kept chilled.
Variations and Substitutions:
Feeling adventurous? Try these tweaks:
- Nutty Brownies: Add chopped pecans or walnuts for a crunchy twist.
- Double Chocolate: Stir in chocolate chunks into the batter for even more chocolate goodness.
- Gluten-Free: Swap all-purpose flour for a 1:1 gluten-free blend.
- Peppermint Brownies: Add a drop of peppermint extract to the frosting for holiday vibes.
What to Serve with Cosmic Brownies Copycat?
Honestly, they’re pretty epic on their own, but if you’re going all out:
- Vanilla Ice Cream: Warm brownie + cold ice cream = heaven.
- Glass of Milk: Classic and perfect.
- Coffee: Balances the sweetness perfectly.
- Strawberries: Because chocolate and berries are always a good idea.
Frequently Asked Questions:
How do I get super clean slices?
Chill the brownies first and use a sharp knife. Wipe between cuts. You got this.
Can I skip the corn syrup?
You can, but the brownies might be slightly less chewy.
Can I make these ahead?
Totally! They’re even better the next day once the ganache sets fully.
These Cosmic Brownies Copycat are pure chocolate nostalgia with a homemade twist. So, what do you think? Ready to whip up a batch? Let me know how they turn out—and if you sneak one before they’re chilled, no judgment here.
<Remember it later>
Planning to try this recipe soon? Pin it for a quick find later!
<Remember it later>
Planning to try this recipe soon? Pin it for a quick find later!
Keep the Flavor Coming – Try These:
Cosmic Brownies Copycat
Ingredients
For the brownies:
- 10 tbsp 142 grams unsalted butter
- 1 c. 200 grams granulated sugar
- 1/3 c. 67 grams packed light brown sugar
- 3/4 c. + 2 tbsp 88 grams unsweetened cocoa powder, sifted
- 1/2 tsp vanilla extract
- 2 large eggs plus 1 egg yolk
- 1 tbsp corn syrup
- 2/3 c. 85 grams all-purpose flour
- 1 tbsp cornstarch
- 1/4 tsp salt
For the frosting:
- 1/2 c. heavy cream
- 1 1/2 c. 255 grams semisweet chocolate chips
- Wilton Rainbow Chip Crunch or mini M&M’s sprinkles, or other candy for decoration
Instructions
- Get ready to make some brownies! Start by preheating your oven to 350°F (175°C). Take an 8 by 8-inch metal baking pan and line it with parchment or foil. Then lightly coat it with cooking spray.
- Now let's prepare the brownie batter. In a bowl that's safe for use in the microwave melt the butter for approximately 90 seconds on high power. Next add in the granulated sugar, brown sugar and sifted cocoa powder. If it's still too hot allow it to cool slightly before adding the vanilla extract, eggs, egg yolk and corn syrup. Stir everything together until well combined. After that incorporate the all-purpose flour, cornstarch and salt into the mixture; stir until combined. The batter will be thick but chocolatey! Pour this concoction into your pan.
- It's time to bake these brownies to perfection! Place your brownie masterpiece into the oven. Let it bake for around 25 minutes. You'll know they're done when the edges are set. The center is still gooey. Once baked thoroughly remove them from the oven and allow them to cool completely while they're still in the pan.
- Moving on to making some frosting; Take a bowl that's safe for use, in the microwave and heat up heavy cream on high power for about 1 minute. Add semisweet chocolate chips to it. Let them sit undisturbed for 3 minutes before stirring until smooth.
- Spread the chocolate ganache evenly over your brownies. Next, you can add a burst of color and flavor by sprinkling Wilton Rainbow Chip Crunch, M&Ms or your preferred candy toppings.
- To allow the frosting to set beautifully chill your brownie pan in the refrigerator for 1 to 2 hours. Once ready cut these creations into 16 squares. These brownies are best enjoyed when chilled and make for a perfect dessert, on any occasion.
Notes
I’m Bitty, owner of nodashofgluten.com, where I share simple, delicious recipes for all tastes, including gluten-free. Check out my “About Me” page for more info!
