Homemade Cosmic Brownie Recipe
Introduction
These homemade cosmic brownies are a delightful treat, combining a rich chocolate base with a creamy ganache topping and colorful rainbow chips. Perfectly fudgy and packed with chocolate, they make a fun and festive dessert for any occasion.

Ingredients
- 1 cup granulated white sugar
- 1 cup brown sugar
- 2 teaspoons vanilla extract
- 1/2 teaspoon salt
- 2 large eggs
- 2 large egg yolks
- 8 tablespoons unsalted butter
- 8 ounces chocolate chips
- ½ cup vegetable oil
- 1 ¼ cups all-purpose flour
- ¼ cup unsweetened cocoa powder
- ½ cup heavy cream
- 1.5 cups chocolate chips
- ¼ cup rainbow chocolate chips
Instructions
- Step 1: Preheat the oven to 350°F (175°C). Line a 9×13 inch baking dish with parchment paper and spray with cooking spray. Set aside.
- Step 2: In a large bowl, whisk together the granulated sugar, brown sugar, vanilla extract, salt, eggs, and egg yolks until fully combined.
- Step 3: In a microwave-safe bowl, melt the butter and 8 ounces of chocolate chips by microwaving for 30 seconds, stirring, then repeating until smooth.
- Step 4: Whisk the vegetable oil into the melted chocolate mixture until incorporated.
- Step 5: Pour the chocolate mixture into the sugar and egg mixture, mixing until well combined. Gently fold in the flour and cocoa powder until just combined.
- Step 6: Pour the brownie batter into the prepared pan and bake for 30 to 35 minutes, or until a toothpick inserted in the center comes out clean.
- Step 7: To make the ganache, heat the heavy cream in a microwave-safe bowl for 1 minute. Add 1.5 cups chocolate chips and let stand for 2 minutes, then stir until smooth.
- Step 8: Pour the ganache evenly over the warm brownies and immediately sprinkle the rainbow chocolate chips on top.
- Step 9: Allow the brownies to cool completely before slicing and serving.
Tips & Variations
- Use good-quality chocolate chips for a richer flavor and smoother ganache.
- If you prefer a fudgier texture, slightly underbake the brownies by 3-5 minutes.
- Substitute rainbow chips with chopped nuts or white chocolate chips for different textures.
Storage
Store the cooled brownies in an airtight container at room temperature for up to 3 days or in the refrigerator for up to a week. To reheat, warm individual pieces briefly in the microwave for about 10 seconds to soften the ganache.
How to Serve

Serve this delicious recipe with your favorite sides.
FAQs
Can I use dark chocolate instead of semi-sweet chocolate chips?
Yes, dark chocolate can be used and will give the brownies a deeper, more intense chocolate flavor. Adjust the amount of sugar slightly if you prefer them less bitter.
Do I have to use vegetable oil in the batter?
Vegetable oil helps keep the brownies moist and tender, but you can substitute it with melted coconut oil or another mild-flavored oil if desired.
PrintHomemade Cosmic Brownie Recipe
This Homemade Cosmic Brownie recipe features rich, fudgy brownies topped with a luscious chocolate ganache and colorful rainbow chocolate chips, delivering a nostalgic and indulgent treat perfect for any occasion.
- Prep Time: 15 minutes
- Cook Time: 35 minutes
- Total Time: 50 minutes
- Yield: 12 servings 1x
- Category: Dessert
- Method: Baking
- Cuisine: American
Ingredients
Brownie Batter
- 1 cup granulated white sugar
- 1 cup brown sugar
- 2 teaspoons vanilla extract
- 1/2 teaspoon salt
- 2 large eggs
- 2 large egg yolks
- 8 Tablespoons unsalted butter
- 8 ounces chocolate chips
- ½ cup vegetable oil
- 1 ¼ cups all-purpose flour
- ¼ cup unsweetened cocoa powder
Ganache
- ½ cup heavy cream
- 1.5 cups chocolate chips
Topping
- ¼ cup Rainbow Chocolate Chips
Instructions
- Prepare Oven and Pan: Preheat your oven to 350°F. Line a 9×13 inch baking dish with parchment paper and generously spray with cooking spray to prevent sticking.
- Mix Sugars and Eggs: In a large bowl, combine granulated sugar, brown sugar, vanilla extract, salt, whole eggs, and egg yolks. Whisk thoroughly until the mixture is smooth and homogenous.
- Melt Butter and Chocolate: Place butter and 8 ounces of chocolate chips in a microwave-safe bowl. Microwave in 30-second intervals, stirring between each, until fully melted and smooth.
- Add Oil to Chocolate: Stir vegetable oil into the melted chocolate mixture until well incorporated.
- Combine Chocolate with Sugar Mixture: Pour the chocolate mixture into the sugar-egg mixture and mix until fully combined.
- Fold in Dry Ingredients: Gently fold in all-purpose flour and cocoa powder, mixing just until combined to avoid overworking the batter.
- Bake the Brownies: Pour the brownie batter into the prepared pan and bake in the preheated oven for 30 to 35 minutes. Check doneness by inserting a toothpick into the center; it should come out clean.
- Heat Cream for Ganache: Pour heavy cream into a microwave-safe bowl and heat in the microwave for 1 minute until just hot but not boiling.
- Prepare Ganache: Add 1.5 cups chocolate chips to the heated cream. Let sit for 2 minutes, then stir vigorously until the ganache is smooth and glossy.
- Apply Ganache and Add Toppings: Pour ganache evenly over the cooled brownies using an offset spatula for smoothness. Immediately sprinkle with rainbow chocolate chips so they stick.
- Cool and Serve: Allow the brownies to cool completely so the ganache sets before slicing into pieces.
Notes
- Use parchment paper for easy removal and clean edges.
- Do not overbake to keep the brownies fudgy.
- Let brownies cool before topping with ganache to prevent melting the chips.
- Microwave melting in short intervals prevents burning the chocolate.
- For added texture, use chunky or salted chocolate chips in the batter.
Keywords: Cosmic Brownies, homemade brownies, chocolate ganache, rainbow chocolate chips, fudgy brownies, easy dessert

