Take a sweet trip back to childhood with these Cosmic Brownie Cookies, a Nostalgic Treat that captures the fudgy magic of classic Cosmic Brownies in a soft, chewy cookie! Topped with rich chocolate ganache and vibrant rainbow sprinkles, these cookies are perfect for parties, bake sales, or a fun family dessert. They’re my go-to when I want to spark joy and satisfy a sweet tooth!
Why You’ll Love Cosmic Brownie Cookies
These Cosmic Brownie Cookies shine as a Nostalgic Treat:
- Retro Vibes: All the Cosmic Brownie flavors in cookie form.
- Easy & Fun: Simple to make, with a playful sprinkle finish.
- Crowd-Pleaser: Kids and adults can’t resist the chocolatey goodness.
- Versatile: Ideal for any occasion, from casual to festive.
I baked these for a friend’s birthday, and they disappeared faster than the cake!
Ingredients for Cosmic Brownie Cookies
Here’s what you’ll need for Cosmic Brownie Cookies (makes ~24 cookies):
Cookies:
- 1 cup unsalted butter, softened
- 1¼ cups granulated sugar
- 2 large eggs
- 2 tsp vanilla extract
- 1¼ cups all-purpose flour
- ¾ cup unsweetened cocoa powder
- 1 tsp baking powder
- ½ tsp kosher salt
Ganache:
- 1 cup semisweet chocolate chips
- ½ cup heavy cream
Topping:
- ¼ cup rainbow sprinkles
Equipment:
- Baking sheet
- Parchment paper
- Electric mixer
Ingredient Tips:
- Butter: Softened for creamy texture; avoid melting to prevent spreading.
- Cocoa Powder: Unsweetened for rich flavor; Dutch-processed for deeper color.
- Chocolate Chips: Semisweet for balance; use high-quality for smoother ganache.
- Sprinkles: Rainbow for classic look; ensure they’re fresh for vibrant color.
- Eggs: Room temperature for better incorporation into dough.
Directions for Cosmic Brownie Cookies
Let’s bake these delightful Cosmic Brownie Cookies!
Preheat and Prep
I preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper to prevent sticking.
Cream Butter and Sugar
In a large bowl, I use an electric mixer to cream 1 cup softened butter and 1¼ cups granulated sugar until light and fluffy, about 2–3 minutes.
Add Wet Ingredients
I add 2 eggs and 2 tsp vanilla extract to the butter-sugar mixture, mixing until fully combined, about 1 minute.
Mix Dry Ingredients
In a separate bowl, I whisk together 1¼ cups flour, ¾ cup cocoa powder, 1 tsp baking powder, and ½ tsp salt until evenly blended.
Combine and Form Cookies
I gradually add the dry ingredients to the wet, mixing until just combined to avoid overmixing. Using a tablespoon, I scoop dough balls onto the baking sheet, spacing them 2 inches apart, and flatten slightly with a spoon.
Bake
I bake for 8–10 minutes, until the edges are set but the centers are soft. I let the cookies cool on the sheet for 5 minutes, then transfer to a wire rack to cool completely.
Make the Ganache
In a microwave-safe bowl, I combine 1 cup chocolate chips and ½ cup heavy cream, microwaving in 30-second intervals, stirring until smooth and glossy, about 1–2 minutes total.
Decorate and Set
I spoon 1 tsp ganache onto each cooled cookie, spreading gently. I sprinkle with rainbow sprinkles and let the ganache set at room temperature for 30 minutes before serving.
Nutrition
- Prep Time: 15 minutes
- Cook Time: 10 minutes
- Total Time: ~45 minutes (plus setting time)
- Yield: ~24 cookies
- Calories: ~180 kcal per cookie
- Macros per Cookie: 20g carbs, 2g protein, 8g fat, 1g fiber
Variations for Cosmic Brownie Cookies
Try these twists on Cosmic Brownie Cookies:
- Minty Fresh: Add ½ tsp peppermint extract to the ganache for a cool Nostalgic Treat.
- Nutty Crunch: Top with chopped peanuts instead of sprinkles for a Nostalgic Treat twist.
- White Chocolate: Use white chocolate chips for a sweeter ganache.
- Gluten-Free: Swap flour for a 1:1 gluten-free baking blend.
- Double Chocolate: Mix ½ cup mini chocolate chips into the dough.
Serving Ideas:
- Pair with Layla Cooks’ Chicken Kiev for a sweet-savory dinner spread.
- Serve with a cold glass of milk to enhance the Nostalgic Treat vibe.
- Display on a colorful platter for a fun party dessert.
Storage
I store Cosmic Brownie Cookies in an airtight container at room temperature for up to 7 days to keep them soft and fresh. For longer storage, I refrigerate them for up to 2 weeks, ensuring they’re tightly sealed to prevent drying out. To freeze, I place cookies in a single layer on a baking sheet to solidify, then transfer to a freezer-safe bag for up to 3 months. I thaw at room temperature before serving, allowing the ganache to soften.
FAQs About Cosmic Brownie Cookies
Here are some common questions about this recipe:
Can I make these cookies ahead of time?
Yes! You can bake Cosmic Brownie Cookies in advance and store them in an airtight container at room temperature for up to a week. For longer storage, freeze and thaw before serving.
Can I use a different type of chocolate for the ganache?
Absolutely! While semisweet chocolate is used in Cosmic Brownie Cookies, you can use milk or dark chocolate. Adjust cream if needed for the right consistency.
What can I use if I don’t have rainbow sprinkles?
If you lack rainbow sprinkles for Cosmic Brownie Cookies, try other sprinkles, mini chocolate chips, or chopped nuts for a different texture and flavor.
Why did my cookies spread too much while baking?
If Cosmic Brownie Cookies spread excessively, ensure butter isn’t too soft, measure flour accurately, and avoid overmixing. Chilling the dough for 30 minutes before baking can help.
More Cookies Ideas You’ll Love
- Peach Cobbler Cookies
- Perfect Soft and Chewy Vegan Sugar Cookies
- Copycat Milano Cookies
- Lemon Gooey Butter Cookies
Conclusion
Cosmic Brownie Cookies are a delightful treat that combines the best of both worlds: the rich, fudgy flavor of brownies and the ease of cookies. Perfect for parties, special occasions, or just because, these cookies are sure to bring a smile to everyone’s face. Enjoy baking and sharing these colorful, nostalgic delights!

Cosmic Brownie Cookies
Ingredients
For the cookies:
- 1 cup unsalted butter softened
- 1 1/4 cups granulated sugar
- 2 large eggs
- 2 teaspoons vanilla extract
- 1 1/4 cups all-purpose flour
- 3/4 cup cocoa powder
- 1 teaspoon baking powder
- 1/2 teaspoon salt
For the ganache:
- 1 cup semisweet chocolate chips
- 1/2 cup heavy cream
For the topping:
- Rainbow sprinkles
Instructions
- Preheat the oven to 350°F (175°C). Line a baking sheet with parchment paper.
- In a large bowl, cream together the butter and sugar until light and fluffy. Add the eggs and vanilla extract, mixing until well combined.
- In a separate bowl, whisk together the flour, cocoa powder, baking powder, and salt. Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
- Scoop tablespoon-sized balls of dough onto the prepared baking sheet, spacing them about 2 inches apart. Flatten each ball slightly with the back of a spoon.
- Bake for 8-10 minutes, or until the edges are set. Allow the cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
- While the cookies are cooling, prepare the ganache. In a microwave-safe bowl, combine the chocolate chips and heavy cream. Microwave in 30-second intervals, stirring between each, until the mixture is smooth and glossy.
- Spoon a small amount of ganache onto the center of each cooled cookie, spreading it slightly. Top with rainbow sprinkles.
- Allow the ganache to set before serving.
Notes
- Store cookies in an airtight container at room temperature for up to a week.
- For longer storage, freeze the cookies and thaw them before serving.
- Customize with different types of sprinkles or toppings.
Did you Like This Recipe? Please Rate and Comment Below!