Cosmic Brownies Recipe

If you grew up craving the chewy, fudgy, chocolate-laden Cosmic Brownies from the lunchroom, you’re going to fall head-over-heels for this homemade version. These Cosmic Brownies are ultra-rich, layered with an unbelievably glossy chocolate icing, and topped with a joyful shower of rainbow sprinkles—irresistible for both kids and nostalgic grown-ups alike!

this Recipe

Ingredients You’ll Need

The ingredient list for homemade Cosmic Brownies is straightforward, but each element is intentional! Every ingredient—from the good-quality chocolate to the dash of vanilla—plays a role in creating brownies with deep flavor, glossy icing, and that signature rainbow sparkle.

• Dark Chocolate (72%): Choose a rich, flavorful bar or chips for a deep, fudgy base—this makes all the difference!
• Unsalted Butter: Brings luxurious richness and keeps the crumb ultra-moist (cold from the fridge is completely fine).
• Dutch Process or Unsweetened Cocoa Powder: Enhances color and gives brownies a more intense chocolate punch—sift for best results.
• Eggs (room temperature): Bind everything together and add structure without making the brownies cakey.
• Caster Sugar: Dissolves smoothly for that beautifully shiny top (granulated sugar works in a pinch).
• Light or Dark Brown Sugar: Brings a gentle molasses flavor and helps keep the interior extra tender.
• Kosher Salt: Just a pinch balances the sweetness and intensifies the chocolate flavor.
• Vanilla Extract or Vanilla Bean Paste: Adds warmth and lovely aromatic notes (your brownies will smell amazing!).
• All-Purpose Flour (sifted): The minimal flour makes the brownies ultra fudgy rather than cakey—don’t skip the sifting!
• Powdered Sugar (for icing): Creates a smooth, melt-in-your-mouth chocolate icing layer.
• Cocoa Powder (for icing): Doubles up the chocolate flavor in the glossy topping.
• More Unsalted Butter (for icing): Ensures the icing is creamy and delicious.
• Boiling Water: Makes the icing pourable and glossy—don’t worry, it sets up perfectly once chilled.
• Rainbow Sprinkles: The happiest finish—use classic “cosmic” dot sprinkles or any festive confetti you love.

Variations

One of the magical things about Cosmic Brownies is how customizable they can be! You can easily tweak this recipe to suit different tastes, allergy needs, or just shake things up for a special occasion. Here are a few crowd-pleasing ideas:

• Gluten-Free Cosmic Brownies: Swap the all-purpose flour for your favorite 1:1 gluten-free blend—no one will know the difference.
• Nutty Twist: Gently fold in a handful of chopped walnuts or pecans for a fun crunch and earthy flavor.
• Peanut Butter Cosmic Brownies: Swirl in some creamy peanut butter into the batter or drizzle on top for peanut butter cup fans.
• Dairy-Free Version: Use high-quality vegan butter and a plant-based chocolate for a luscious, totally dairy-free treat.

How to Make Cosmic Brownies

Step 1: Melt the Chocolate and Butter

Start by lining a 9×13-inch pan with parchment paper, leaving some overhang for easy lifting later. Next, melt the chopped dark chocolate and cold butter together over a double boiler or in short microwave bursts, stirring often until silky smooth and thoroughly blended—this step is crucial for that shiny, fudgy crumb.

Step 2: Mix Cocoa Powder In

Sift the cocoa powder right over your warm chocolate-butter mixture, then stir until it disappears—this doubles down on chocolate flavor and ensures a gorgeous dark color without pesky lumps.

Step 3: Whip Eggs and Sugars

In a large bowl, combine the eggs, caster sugar, and brown sugar. Use a hand mixer or stand mixer with a whisk attachment to beat for 2-3 minutes, until pale and noticeably increased in volume—this gives your brownies structure and that luscious, slightly chewy bite.

Step 4: Combine Wet and Dry Elements

Pour the chocolate-butter mixture into the whipped eggs and sugars, then add in salt and vanilla. Mix thoroughly until smooth, then gently fold in the sifted flour by hand—overmixing can make brownies tough, so stir just until the last bits of flour disappear.

Step 5: Bake the Brownies

Scrape the batter into the prepared pan and tap it on the counter a couple of times to smooth and release any air bubbles. Bake at 350°F (180°C) for 18–20 minutes, checking after 15. The edges and top should be set, but the center should yield a few moist crumbs when tested with a skewer—don’t overbake for that signature chewy texture.

Step 6: Prepare and Pour the Icing

While the brownies cool for 5 minutes, sift together powdered sugar, cocoa, and salt in a clean bowl. Add softened butter and boiling water, mixing first with a spatula, then a whisk, until you have a glossy, pourable icing. Immediately pour over the still-warm brownies and use an offset spatula to smooth.

Step 7: Add Sprinkles and Chill

Give the icing a minute or two to settle, then liberally sprinkle your brownies with colorful “cosmic” sprinkles. Chill in the fridge for several hours, or overnight for ultra-clean slicing—this helps the icing set perfectly and makes cutting a breeze.

Step 8: Slice and Serve

Once chilled, use the parchment sling to lift the brownies out. Slice into squares with a sharp knife (wipe between cuts for the neatest edges), and get ready for the best homemade Cosmic Brownies ever!

How to Serve Cosmic Brownies

Garnishes

You simply can’t skip the rainbow sprinkles—the more playful and vibrant, the better for truly authentic Cosmic Brownies! For fun, try edible glitter, gold stars, or even a pinch of flaky sea salt for an adult twist. If you’re feeling extra, swirl a touch of melted white chocolate over the iced top before adding sprinkles.

Side Dishes

Pair your brownies with a scoop of vanilla ice cream for a dessert that hits every comfort-food note, or serve alongside fresh berries to balance the chocolatey richness. A cold glass of milk or an iced mocha really takes the Cosmic Brownies experience over the top!

Creative Ways to Present

For parties or bake sales, cut the brownies into bite-sized “galaxy bars,” skewer them on popsicle sticks, or package individually in cellophane bags with a splash of extra sprinkles. You can even use cookie cutters to create star or heart-shaped brownies for birthdays and celebrations.

Make Ahead and Storage

Storing Leftovers

Store leftover Cosmic Brownies in an airtight container in the refrigerator for up to 5 days—the flavors will continue to develop and the icing stays perfectly set (if they last that long!).

Freezing

Cosmic Brownies freeze beautifully! Once chilled and sliced, wrap each square in plastic wrap, then place in a freezer-safe bag or container. Freeze for up to 2 months, and thaw in the fridge or on the counter when a craving strikes.

Reheating

While Cosmic Brownies are delicious cold or at room temp, you can soften a chilled square for 10–15 seconds in the microwave for a gooey, extra-chocolatey treat. Add a scoop of ice cream and you’ve got brownie sundae heaven!

FAQs

Final Thoughts

These homemade Cosmic Brownies check every box—fudgy, chocolate-packed, and topped with a shower of joyful rainbow sprinkles. They’re the kind of treat that sparks pure happiness from the very first bite. Give this nostalgic recipe a try and share a little cosmic wonder with your friends, your family, or just your own inner child. Enjoy every glorious, chocolatey square!

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