Homemade Cosmic Brownies: The Ultimate Fudgy Copycat Recipe!

Get ready to embark on a nostalgic journey with these incredible homemade Cosmic Brownies! If you’re a fan of the classic Little Debbie treat, prepare to be amazed, because this copycat recipe delivers everything you love and more. These brownies are exceptionally thick, wonderfully fudgy, and perfectly moist, crowned with a lusciously rich layer of homemade chocolate ganache and adorned with those signature vibrant cosmic candies. Forget the store-bought version; once you taste these, you’ll never go back!

It’s no secret that I have a deep adoration for brownies, as evidenced by the many brownie recipes I’ve shared over time. My Nutella brownies have become a fan favorite, inspiring me to continuously explore and perfect more delicious brownie variations for you to enjoy. Some personal highlights include my decadent German chocolate brownie bars, topped with gooey coconut pecan frosting, my spot-on copycat BYU mint brownies, and the comforting classic lunch lady brownies. But these Cosmic Brownies? They hold a special place for their irresistible combination of deep chocolate flavor and playful crunch.

Why This Homemade Cosmic Brownie Recipe Works So Well

• Unmatched Chocolate Flavor and Texture: Whether it’s classic fudgy brownies or innovative brownie cookies, my ultimate love for brownies stems from their intensely rich chocolate flavor and luxuriously creamy, thick texture. This Cosmic Brownies recipe excels on both these fronts, delivering a deep, satisfying chocolate experience in every bite that truly melts in your mouth.
• Achieving that Signature Dense, Fudgy Texture: The secret to these incredibly thick and dense brownies lies in a special ingredient: a touch of cornstarch in the brownie batter. Cornstarch helps to inhibit gluten development in the flour, resulting in a remarkably tender, chewy, and dense chocolate bar – that perfect fudgy consistency we all crave in a brownie, akin to your favorite candy bar.
• Superior Chocolate Ganache (Not Frosting!): One of the critical elements that elevates these homemade Cosmic Brownies is our decision to use a silky-smooth chocolate ganache instead of traditional chocolate frosting. Homemade chocolate ganache is truly superior on brownies, and for good reason! It’s intensely rich, wonderfully creamy, and provides a deep chocolate flavor without being overly sweet. While frosting can sometimes feel heavy or cloying, prompting you to scrape some off, ganache offers a more refined and balanced sweetness. Plus, I’ll share my best tips and tricks to ensure you achieve a perfectly smooth, glossy ganache every single time.
• Effortless Removal and Clean Cuts: We take the hassle out of baking by lining the pan with foil (or parchment paper). This simple step ensures that removing the entire slab of brownies from the pan is a breeze, making cutting them into neat, even squares incredibly easy and mess-free. No more sticky edges or crumbled brownies!

Essential Ingredients for Your Cosmic Brownies

Crafting the perfect batch of homemade Cosmic Brownies starts with understanding the role of each ingredient. Here’s what you’ll need to create these out-of-this-world treats, ensuring that signature fudgy texture and rich chocolate flavor:

Cosmic Brownie Base Ingredients

• Granulated Sugar: This provides sweetness and helps create that slight crispness on the brownie’s crust, contributing to overall texture. Using both granulated and brown sugar is key, as they play distinct roles in color, texture, and flavor.
• Light Brown Sugar: This sugar is crucial for moisture and a deeper, more caramel-like flavor. It also adds to the chewiness of the brownies. While you *can* use dark brown sugar for an even richer taste, light brown sugar offers a perfect balance. Ensure it’s packed when measuring for accuracy.
• Unsalted Butter: We opt for melted butter over softened butter. Why? Melted butter significantly contributes to a fudgier, denser brownie with a more intense chocolate flavor, as opposed to a cake-like texture. It also helps bind the ingredients beautifully.
• Eggs and Egg Yolk: The whole eggs act as a primary binder and provide structure. The addition of an extra egg yolk is a secret weapon for super fudgy brownies! The extra fat from the yolk, with less protein than a whole egg, creates a richer, more tender, and intensely fudgy crumb that melts in your mouth.
• Vanilla Extract: Far from just a background flavor, vanilla extract is vital for balancing and enhancing the rich chocolate notes, ensuring the brownies aren’t one-dimensionally sweet but boast a complex, well-rounded flavor profile.
• All-Purpose Flour: This is the fundamental starch base for our brownies, providing just enough structure without making them cakey. Avoid overmixing, as this can develop too much gluten and result in tougher brownies.
• Unsweetened Cocoa Powder: The heart of our chocolate flavor! I recommend using unsweetened natural cocoa powder for a deep, authentic chocolate taste. The quality of your cocoa powder will directly impact the richness of your Cosmic Brownies.
• Cornstarch: As mentioned, cornstarch is key to achieving that beloved thick, dense, and ultra-creamy brownie base. It’s the secret ingredient that pushes these brownies into extraordinary fudginess.
• Pinch of Salt: Essential for enhancing all the other flavors, especially the chocolate, and balancing the sweetness.
• Rainbow Chips (Cosmic Candies): These are the iconic little colorful bits that give Cosmic Brownies their name and signature look. They are slightly different from mini colored M&Ms, but you can certainly use those if you can’t find the specific rainbow chips. You can often find rainbow chips on Amazon, here, or at specialty baking stores.

Homemade Chocolate Ganache Ingredients

The luxurious topping for our Cosmic Brownies requires just two simple ingredients:

• Semi-Sweet Chocolate: You can use finely chopped semi-sweet chocolate bars for the best melt and flavor, or good quality semi-sweet chocolate chips for convenience. The semi-sweet variety provides a perfect counterpoint to the sweetness of the brownie base.
• Heavy Cream: Also known as heavy whipping cream, this provides the richness and emulsifies with the chocolate to create that incredibly smooth, glossy ganache.
• Pinch of Salt: A tiny bit of salt in the ganache helps to deepen the chocolate flavor and cut through the richness, making it even more addictive.

Easy Step-by-Step Instructions to Make Cosmic Brownies

Creating these fudgy, chocolatey treats is simpler than you might think! Follow these detailed steps for the best homemade Cosmic Brownies:

How to Make the Fudgy Brownie Base

1. First, preheat your oven to 350°F (175°C). Prepare a 13×9 inch baking pan by lining it with either parchment paper or aluminum foil, ensuring you leave an overhang on the sides to create “handles” for easy removal. If using foil, lightly spray it with cooking spray to prevent sticking.
2. In a large mixing bowl or the bowl of a stand mixer fitted with a paddle attachment, combine the melted unsalted butter, light brown sugar, and granulated sugar. Beat these ingredients together on medium speed for a full 2-3 minutes. This step is crucial for incorporating air and creating that slightly crisp top crust. You’ll notice the mixture becoming lighter in color and fluffy.

3. Add the large eggs and the extra egg yolk to the butter-sugar mixture, one at a time, beating well after each addition until fully incorporated. This ensures a smooth batter. Then, stir in the vanilla extract and mix briefly until just combined.

4. In a separate small bowl, whisk together the dry ingredients: all-purpose flour, unsweetened cocoa powder, cornstarch, and a pinch of salt. Whisking ensures that the cornstarch and cocoa are evenly distributed, which is crucial for uniform texture in the final brownies.
5. Gradually add the dry ingredient mixture to the wet ingredients. Mix on low speed, or by hand with a spatula, until just combined. Be careful not to overmix the batter; overmixing can lead to tough brownies. The batter will be quite thick, which is exactly what we want for that dense, fudgy consistency!

6. Once the batter is mixed, spoon it into your prepared 13×9 inch pan. Using an offset spatula or the back of a spoon, gently spread and level the batter into an even layer across the entire pan. This ensures even baking.
7. Bake for 18-24 minutes. Baking times can vary by oven, so keep a close eye on them. The brownies are done when a toothpick inserted into the center comes out with moist crumbs, but not wet batter. Avoid overbaking to maintain their fudgy texture. As the brownies near completion, you can begin preparing your chocolate ganache.

Crafting the Silky Smooth Chocolate Ganache

The ganache is simple but requires a little patience for perfection!

1. Place your finely chopped semi-sweet chocolate (or chocolate chips) in a medium-sized, heat-proof bowl. Ensure the chocolate is in small, uniform pieces for even melting.
2. In a small saucepan over medium heat, gently warm the heavy cream. Bring it to a bare simmer – you’ll see small bubbles forming around the edges, but don’t let it come to a rolling boil. As soon as it’s almost boiling, remove the saucepan from the heat and immediately pour the hot heavy cream over the chocolate. Add a pinch of salt. Now, this is the crucial part: let the hot heavy cream sit over the chocolate for at least 3 minutes *before* stirring. This waiting period allows the residual heat of the cream to melt the chocolate gently and evenly, preventing it from seizing or becoming gritty.

3. After the 3 minutes, grab a small whisk and begin stirring the cream and chocolate. Start whisking slowly in the very center of the bowl, gradually expanding your circles outwards towards the edges. Continue whisking gently until the mixture is completely smooth, glossy, and emulsified into a beautiful ganache. This technique helps create a perfectly stable and smooth emulsion.

4. Once the ganache is smooth, let it sit for another 4-5 minutes to cool slightly and thicken to a pourable but not too runny consistency. Then, generously pour it over the brownies, which should be cooled but not completely cold (lukewarm is ideal). Use a spatula to gently spread the ganache into an even, luscious layer over the entire surface of the brownies.
5. Immediately after spreading the ganache, sprinkle generously with the vibrant rainbow chips (cosmic candies). Don’t wait too long, as the ganache will begin to set.
6. Allow the ganache on the brownies to fully set before cutting and serving. This is important for clean cuts and to prevent the ganache from sliding off. You can let them sit at room temperature for 2-3 hours, or place them in the refrigerator for about 45 minutes to an hour to speed up the setting process. Once set, lift the brownies out of the pan using the foil/parchment handles and cut into squares.

Expert Tips for Perfect Cosmic Brownies Every Time

Brownie Baking Tips

• Do Not Overbake! This is hands down the biggest culprit behind dry, cakey brownies. Every oven is unique, so baking times can vary slightly. The ideal doneness for fudgy brownies is when a toothpick inserted into the center comes out with moist crumbs attached, but no wet batter. A completely clean toothpick means they are likely overdone.
• Cooling is Crucial: Once baked, remove the brownies from the oven and let them cool in the pan. While they don’t need to be fully chilled before applying the ganache, they should be significantly cooler than piping hot. Cooling allows the brownies to set properly and prevents the ganache from melting into a messy puddle.
• Thoroughly Whisk Dry Ingredients: Because this recipe includes cornstarch, it’s particularly important to whisk all your dry ingredients (flour, cocoa powder, cornstarch, salt) together thoroughly in a separate bowl before adding them to the wet mixture. This ensures even distribution of the cornstarch, leading to a consistent, thick, and fudgy texture across the entire pan of brownies.
• Pan Size Matters: This recipe is designed for a 13×9 inch baking pan. Using a different size can alter baking times and the thickness of your brownies. If you use a smaller pan, your brownies will be thicker and may need a longer baking time; a larger pan will result in thinner brownies requiring less time.

Are you more of a cookie fan? You might love my Crumbl Cosmic Brownie Cookies for a chewy, delightful variation!

Ganache Perfection Tips

• Chocolate Choice: You can use 1 1/4 cups of good quality semi-sweet chocolate chips or 8 oz of finely chopped semi-sweet chocolate. I often use chocolate chips for convenience as they are a pantry staple for me. For a unique flavor twist, consider using a variation of chocolate, such as half milk chocolate and half semi-sweet chocolate chips for a slightly sweeter, creamier ganache.
• Patience is Key for Emulsification: This is a critical step for perfect ganache. You must let the hot cream sit over the chocolate for at least 3 minutes *before* stirring. This crucial waiting period allows the hot cream to gently melt the chocolate, while simultaneously bringing down the temperature of the cream. If you whisk the cream and chocolate while the cream is still extremely hot, it can cause the ganache to “break” or separate, resulting in an unappealing gritty or oily texture. This rest period ensures a smooth, stable, and glossy emulsion.
• Timing Your Ganache: Don’t start making your ganache too early. Ideally, begin preparing it just a few minutes before your brownies are ready to come out of the oven. You want the ganache to be perfectly warm and pourable when the brownies are ready for it. If it hardens in the bowl while your brownies are still baking or cooling, you’ll have to gently rewarm it, which can sometimes affect its texture.
• Spreading the Ganache: For the smoothest, most even layer, use an offset spatula to spread the ganache. Work quickly but gently to cover the entire surface of the brownies before the ganache starts to set.

Frequently Asked Questions About Cosmic Brownies

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Did you try this amazing homemade Cosmic Brownies recipe? I would absolutely love to hear about your experience! Click here to leave a star rating and a review, or simply scroll down below the recipe card to share your thoughts. Your feedback helps other bakers, and I appreciate it!

This recipe was originally published on Aug. 26, 2019. It was republished on July 15, 2021, to include additional information and photos, and further optimized for SEO and readability on this date.