Small Batch Cosmic Brownies

These small batch Cosmic Brownies are rich, fudgy, and topped with a thick layer of chocolate ganache and colorful rainbow chips. Baked in a loaf pan, the recipe makes just 4 brownies (or 8 smaller squares), so you can satisfy that nostalgic chocolate craving without making an entire pan.

 

Cosmic Brownies were definitely one of those treats I loved growing up, so naturally I had to give them my Small Sweets treatment. I wanted all the things I remember about them — lots of chocolate, a super fudgy texture, and those colorful little candies on top — but in a homemade version.

I used my small batch brownies recipe as the base and topped with a classic chocolate ganache and those signature rainbow chips. I mean is it even a cosmic brownie if it doesn’t have those on top. I think not.

And because we’re making only four brownies, everything gets baked in a loaf pan. I actually like pulling mine from the oven around the 20-minute mark so they’re slightly underdone in the center. Once they cool, they become wonderfully fudgy — especially underneath that layer of chocolate ganache.

Why This Recipe Works

• It makes just 4 brownies. Everything bakes in an 8×4-inch loaf pan, making this perfect when you’re craving brownies but don’t need a full batch.
• Melted chocolate and Dutch-process cocoa make them extra chocolatey. Using both gives you a deeper chocolate flavor than relying on cocoa powder alone.
• Oil and melted butter give you the best of both worlds. Oil helps keep the brownies moist and fudgy, while butter adds flavor.
• Chocolate ganache makes these taste extra decadent. The smooth chocolate topping and rainbow chips give you that nostalgic Cosmic Brownie look and flavor.

Ingredients Needed

For The Brownies

• All-purpose flour: For the most accurate results, weigh your flour with a kitchen scale or spoon it into your measuring cup and level it off. Too much flour can make your brownies cakey instead of fudgy.
• Salt
• Baking powder
• Egg: Let your egg come to room temperature before mixing so it incorporates easily into the batter.
• Granulated sugar
• Light brown sugar: Make sure to pack the brown sugar into your measuring spoon.
• Canola oil: Another neutral-flavored oil, such as vegetable oil, can also be used.
• Vanilla extract
• Unsalted butter – Salted butter works, just omit the added salt.
• Semi-sweet or bittersweet chocolate: Chop the chocolate into small pieces so it melts quickly and evenly.
• Dutch-process cocoa powder: Dutch-process cocoa gives these brownies a darker color and rich chocolate flavor.
• Chocolate chips: Makes for a fudgy brownie but also helps to create that shiny crust. Don’t skip them!

For The Topping

• Heavy cream: Don’t substitute milk here. You need the higher fat content of heavy cream to make a thick ganache.
• Semi-sweet chocolate – You can chop a chocolate bar or use chocolate chips.
• Rainbow chips: These give the brownies their classic Cosmic Brownie look. You can also use mini rainbow-coated chocolate candies if that’s what you can find.

How To Make Small Batch Cosmic Brownies

1. Prepare your pan and oven.

Position a rack in the center of your oven and preheat the oven to 350°F (180°C). Line an 8×4-inch loaf pan with parchment paper, leaving some overhang on the sides so you can easily lift the brownies out later. You can also grease the pan with non-stick cooking spray.

2. Whisk together the wet ingredients.

In a large mixing bowl, whisk together the egg, granulated sugar, brown sugar, canola oil, and vanilla extract until smooth and combined. Make sure to break up any lumps of brown sugar as you whisk.

3. Melt the butter and chocolate.

In a small saucepan over low heat, melt the butter and chopped chocolate together, stirring frequently so the chocolate doesn’t burn.

Remove the saucepan from the heat and whisk in the Dutch-process cocoa powder until smooth. Adding the cocoa powder to the warm chocolate mixture helps bring out its rich chocolate flavor.

4. Combine the chocolate and egg mixtures.

Pour the melted chocolate mixture into the egg and sugar mixture and whisk until smooth and evenly combined.

If your chocolate mixture is still very hot, let it cool for a couple of minutes first. You don’t want piping-hot chocolate coming into contact with the egg.

5. Add the dry ingredients.

Add the flour, salt, and baking powder directly to the brownie mixture. Use a spatula or wooden spoon to gently stir everything together just until you no longer see streaks of flour.

There’s no need to whisk the dry ingredients together in a separate bowl first. Just make sure the baking powder and salt are sprinkled evenly over the batter rather than added in one concentrated spot.

Fold in the chocolate chips and give a couple of stirs.

6. Bake the brownies.

Spread the batter into the prepared loaf pan and smooth the top into an even layer.

Bake for 20 to 25 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs attached.

I like to pull mine from the oven around the 20-minute mark so they’re a little underdone and extra fudgy. Don’t wait for the toothpick to come out completely clean — that’s usually a sign the brownies have gone a little too far.

Transfer the pan to a wire rack and let the brownies cool completely before adding the ganache.

7. Make the chocolate ganache.

Place the heavy cream in a microwave-safe bowl and heat until very hot and steaming but not boiling, about 30 seconds to 1 minute depending on your microwave.

Add the chocolate chips to the hot cream and let the mixture sit undisturbed for 3 minutes. This gives the hot cream time to gently melt the chocolate.

After 3 minutes, stir until the chocolate and cream come together into a smooth, glossy ganache.

8. Decorate and chill.

Once the brownies are completely cool, spread the chocolate ganache evenly over the top. Immediately sprinkle with the rainbow chips so they stick to the ganache.

Refrigerate for about 15 minutes, or until the ganache is set.

Use the parchment paper overhang to lift the brownies out of the loaf pan. Slice into 4 brownies and enjoy. I like to score the brownies down the middle, not quite cutting all the way through. Then cut into four equal rectangles. They look just like the store-bought ones!

Recipe Tips

• Do not overmeasure your flour. Even a little too much flour matters in a small batch recipe and can turn your fudgy brownies into cakey brownies. For best results, weigh the flour using a kitchen scale.
• Keep the heat low when melting the chocolate. Chocolate can burn quickly, so melt the butter and chocolate together over low heat and stir frequently.
• Do not overmix after adding the flour. Stir only until you no longer see streaks of flour. Overmixing can give your brownies a tougher texture.
• Slightly underbake for fudgier brownies. I prefer baking these for about 20 minutes so the center stays extra fudgy. Look for moist crumbs on your toothpick rather than waiting for it to come out completely clean.
• Let the brownies cool completely before adding the ganache. If the brownies are still warm, the ganache can melt and become too thin instead of sitting in a thick layer on top.

How To Store Small Batch Cosmic Brownies

You can store these Cosmic Brownies in an airtight container at room temperature for up to 2 days. Because of the ganache topping, I prefer storing them in the refrigerator if I’m keeping them any longer.

Store the brownies covered in the refrigerator for up to 5 days. Let them sit at room temperature for about 15 to 20 minutes before serving if you prefer a softer, fudgier texture.

To freeze the baked brownies, let the ganache set completely, then wrap individual brownies in plastic wrap and place them in a freezer-safe bag or container. Freeze for up to 2 months. Thaw overnight in the refrigerator or at room temperature before serving.

Recipe FAQs

More Small Batch Desserts To Try

If you loved these small batch Cosmic Brownies, here are a few more Small Sweets to make next:

• Brownies for Two: Rich, fudgy brownies when you want an even smaller chocolate treat.
• Small Batch Chocolate Chip Cookies: Classic chewy chocolate chip cookies without making a couple dozen.
• Small Batch Cookie Bars: Soft and chewy chocolate chip cookie bars baked right in a loaf pan.
• Mini Chocolate Cake: A rich chocolate cake baked in a 6-inch pan that’s perfect for a smaller celebration.
• Small Batch Cheesecake: Creamy classic cheesecake baked in a loaf pan with no water bath needed.