The perfect brownies for celebrating, topped with whipped chocolate ganache and rainbow sprinkles. Making these Birthday Brownies from Brownie Mix is so easy you can prepare them in no time.

Upgrade your boxed brownies in 7 other ways:
- Cheesecake Brownies from Brownie Mix
- Brookie Bars from Brownie Mix
- Oreo Brownies from Brownie Mix
- Peanut Butter Brownies from Brownie Mix
- Nutty Brownies from Brownie Mix
- S'mores Brownies from Brownie Mix
- Salted Caramel Pretzel Brownies from Brownie Mix
Jump to:
Ingredients you'll need
For the brownie base
For the chocolate ganache
Notes and substitutions
- Brownie Mix: Use a regular-size (about 18 ounces) boxed brownie.
- Water: Replace with milk, buttermilk, or brewed coffee to add richness and flavor.
- Instant coffee: An optional ingredient that enhances the chocolate flavor and tames the sweetness of the brownies.
Tips for best brownies
- Bring eggs to room temperature and lightly beat them to incorporate them well without overmixing.
- Grease and line the pan with parchment paper to prevent the brownies from sticking.
- To avoid overbaking, check the brownies with a toothpick 2 minutes before they are done. Look for several separate crumbs for fudgy brownies and less for cakey brownies.
- Cool the brownies before slicing. Refrigerating them improves their texture.
How to make this recipe
(1)Make the brownie batter as directed in the package and spread it on an 8x8-inch pan. (2)Bake it, then let it cool.
(3)Pour ¾ cup of hot cream over 4 ounces of chocolate in a bowl. Let the chocolate melt for about 2 minutes. (4)Stir until smooth. Refrigerate to slightly cool the mixture, about 30 minutes.
(5)Using a hand mixer, whip on medium-high speed until fluffy and lighter in color for about 3 minutes. (6)Spread the whipped ganache evenly on the cooled brownie. Decorate with rainbow sprinkles.
Let the birthday brownies set for at least an hour in the fridge before cutting. Refrigerate leftovers and consume them within 5 to 7 days.
Frequently asked questions
Eggs at room temperature blend easily with other ingredients. Baked goods will rise evenly and have a uniform texture.
Use a neutral-flavored oil for baking, such as canola or other vegetable oils. I also like mild-tasting oils like avocado oil, olive oil, and coconut oil.
Overwhipping ganache makes it grainy. When you start with a cooled ganache, it only takes one to 3 minutes to become fluffy and lighter in color. If it has turned grainy, reheat it in a double boiler and start over.
More about brownies
If you'd like to know more, here are frequently asked questions on box brownies, including extra tips, troubleshooting, and more.
Other dessert recipes you may like
Did you make this recipe? I would love to know! Your feedback helps me make better recipes. Please rate, review, or comment below. Questions about this recipe are welcome, too!
Let's connect on Facebook, Instagram, Pinterest, TikTok, Twitter, and Youtube. Be sure to tag me when you try any of my recipes @recipesbynora!
📖 Recipe
Birthday Brownies From Brownie Mix
Equipment
- 8x8-inch pan
- Hand mixer
Ingredients
For the brownie base (see package)
- brownie mix about 18 ounces
- eggs room temp & lightly beaten
- water sub:milk, buttermilk, or coffee
- oil (canola, olive, or other vegetable oils)
- ½ teaspoon instant coffee or ¼ teaspoon espresso powder optional
For the frosting
- ¾ cup heavy cream hot
- 4 ounces dark chocolate (bittersweet or semisweet) chips or finely chopped
- 2 tablespoons rainbow sprinkles
Instructions
- Make the brownie batter as directed in the package and spread it on an 8x8-inch pan.
- Bake it, then let it cool.
- Pour the hot cream over the chocolate in a bowl. Let the chocolate melt for about 2 minutes.
- Stir until smooth. Refrigerate to slightly cool the mixture for about 30 minutes.
- Using a hand mixer, whip on medium-high speed until fluffy and lighter in color for about 3 minutes.
- Spread the whipped ganache evenly on the cooled brownie. Decorate with rainbow sprinkles.
- Let it set for at least an hour in the fridge before cutting.
Video
Notes
- Bring eggs to room temperature and lightly beat them to incorporate them well without overmixing.
- Grease and line the pan with parchment paper to prevent the brownies from sticking.
- To avoid overbaking, check the brownies with a toothpick 2 minutes before they are done. Look for several separate crumbs for fudgy brownies and less for cakey brownies.
- Cool the brownies before slicing. Refrigerating them improves their texture.
Thanks for coming! Let me know what you think: