Cosmic Brownies Recipe

Step into chocolate bliss with these homemade Cosmic Brownies—just like the iconic childhood treat, but even richer, softer, and fudgier! Each square is dense and chocolaty, crowned with a luscious fudge icing and a shower of rainbow sprinkles for a playful finish that no one—adult or kid—can resist.

Ingredients You’ll Need

Homemade Cosmic Brownies are all about starting with staple ingredients and treating each one with a bit of care. Each component—from rich chocolate to the rainbow sprinkles—builds irresistible layers of flavor and texture that make this recipe so special.

• Dark chocolate (72% recommended): Gives the brownies deep, intense chocolate flavor—don’t skimp on quality here!
• Unsalted butter: Adds richness and delivers that signature melt-in-your-mouth crumb.
• Dutch process or regular cocoa powder: Enhances color and bumps up the chocolate intensity.
• Large eggs: Help bind the batter and give the brownies their fudgy, dense texture.
• Caster sugar: Dissolves swiftly for a fine-crumbed, glossy finish.
• Brown sugar (light or dark): Lends moisture and a subtle caramel note that deepens the chocolate flavor.
• Kosher salt: Just a touch balances the sweetness and brings out all those bold, chocolaty notes.
• Vanilla extract or paste: Adds comforting warmth and aroma.
• All-purpose flour: The backbone of the brownies—keep it sifted to avoid lumps.
• Powdered sugar: Essential for a smooth, creamy icing.
• Cocoa powder (for icing): Gives your icing its rich chocolate punch—either Dutch or natural works.
• Butter (for icing): Creates silkiness in the fudge topping.
• Boiling water: Helps melt the butter and bring the icing together into that perfect glossy puddle.
• Rainbow sprinkles: The whimsical finishing touch that transforms these from brownies to “Cosmic Brownies”!

Variations

The magic of Cosmic Brownies is that you can absolutely make them your own! Whether you need to brainstorm for allergies, want to shake things up for a themed party, or simply adore a different flavor profile, this is a recipe that welcomes swaps and twists.

• Gluten-Free Cosmic Brownies: Swap the all-purpose flour for your favorite 1:1 gluten-free baking mix to make them perfect for celiac or gluten-sensitive friends.
• Dairy-Free Version: Use vegan butter and a dairy-free chocolate for both the brownie and icing—the results will still be indulgently rich!
• Nutty Cosmic Brownies: Stir in ¾ cup of chopped toasted walnuts or pecans for added crunch and a delicious contrast to the fudgy texture.
• Themed Sprinkles: Go wild with star-shaped sprinkles, mini chocolate chips, or holiday-inspired decorations to suit the season or occasion.

How to Make Cosmic Brownies

Step 1: Prep Your Pan and Ingredients

Preheat your oven to 350°F (180°C), and line a 9×13-inch baking pan with parchment paper, leaving a little overhang on the sides. This simple trick ensures effortless brownie removal and picture-perfect squares. Weigh out and sift your cocoa and flour, chop the chocolate, and get those eggs to room temperature—mise en place makes everything smoother!

Step 2: Melt Chocolate and Butter Together

Combine your chopped dark chocolate and butter in a heatproof bowl set over a pot of simmering water (or use the microwave in short bursts). Stir frequently until silky and smooth, then sift in the cocoa powder and mix thoroughly. This chocolate “base” is where the decadent flavor really begins.

Step 3: Whip Eggs and Sugars

In a large mixing bowl, beat together the eggs, caster sugar, and brown sugar for 2-3 minutes on medium-high using a hand or stand mixer. You’ll see the mixture become pale and voluminous—this is the secret to that classic shiny brownie top and a perfectly dense crumb.

Step 4: Mix and Fold the Batter

Gently mix the melted chocolate mixture into your fluffy egg-sugar blend, then stir in the salt and vanilla extract. Fold in the sifted flour by hand, just until no dry patches remain—the less you mix, the fudgier your Cosmic Brownies will be!

Step 5: Bake to Fudgy Perfection

Pour the batter into the lined pan, tap it firmly on the counter to remove big air bubbles, and smooth the top. Bake for 18–20 minutes, checking at 15. You’re aiming for set edges and a skewer with moist crumbs—err on the side of just-baked for maximum fudginess.

Step 6: Make the Chocolate Icing

While the brownies rest for a few minutes, sift together powdered sugar, cocoa, and a pinch of salt. Add softened butter, toss to coat, and then stir in boiling water to create a glossy, pourable icing. A spatula followed by a quick whisk does the job beautifully here.

Step 7: Ice, Sprinkle, and Chill

Spoon the icing over the warm brownies, smoothing it to the edges—the heat will make everything meltingly luscious. Wait a minute or two before adding a generous flurry of rainbow sprinkles (they’ll stay vibrant this way). Chill in the fridge for a few hours, then lift, slice, and savor your homemade Cosmic Brownies!

How to Serve Cosmic Brownies

Garnishes

Rainbow sprinkles are the absolute must-have, but you can also add a dusting of extra cocoa powder or a drizzle of melted white chocolate for extra flair. A pinch of flaky sea salt right on top brings out the deep chocolate flavor and gives a grown-up twist!

Side Dishes

Cosmic Brownies pair beautifully with a tall glass of cold milk, a scoop of vanilla ice cream, or even alongside fresh berries to offset the richness. For a special dessert spread, slice them smaller and serve with espresso shots or a pot of hot coffee.

Creative Ways to Present

Cut the brownies into tiny squares for party platters, stack with popsicle sticks for cosmic brownie “pops,” or arrange in a rainbow sprinkle-lined box for a homemade gift. For birthdays, adding edible glitter or themed sprinkles takes the “cosmic” theme to the next level!

Make Ahead and Storage

Storing Leftovers

Keep leftover brownies in an airtight container in the fridge, where they’ll stay chewy, fudgy, and delicious for up to 5 days. The icing sets up even more beautifully, so don’t hesitate to make them ahead for lunchboxes or easy snacking.

Freezing

To freeze, slice Cosmic Brownies and separate the layers with parchment. Wrap tightly or use a zip-top bag; they’ll keep well for up to 2 months. Thaw overnight in the fridge or at room temperature before enjoying.

Reheating

Brownies are best enjoyed chilled or at room temp, thanks to that fudge icing. If you want extra gooiness, microwave a piece for 10-15 seconds (just be mindful—icing gets melty fast!).

FAQs

Final Thoughts

If you grew up loving those iconic lunchbox brownies, homemade Cosmic Brownies bring the nostalgia—with a grown-up upgrade! There’s nothing better than sharing a tray of these rich, fudgy bars with friends or family, so give them a try and let the chocolatey fun (and sprinkles) begin!

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