These are the perfect celebration brownies with whipped ganache frosting and rainbow sprinkles. Making these birthday brownies from brownie mix is so easy you can prepare them in no time.

You can also upgrade your boxed brownies in seven 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
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Ingredients you'll need
For the brownie layer
For the chocolate ganache frosting
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 the eggs to room temperature and lightly beat them to ensure they get incorporated well without overmixing.
- Grease and line the pan with parchment paper so the brownies will not stick and come out easily.
- Check the brownies two minutes before they should be done. Test with a toothpick — it should come out with several separate crumbs for fudgy brownies and less for cakey.
- Cool the brownies before slicing. Refrigerating them improves their texture.
How to make this recipe
(1)Make the brownie layer according to package instructions. Spread it evenly on an 8x8-inch pan. (2)Bake, then let it cool.
(3)Heat the heavy cream in the microwave or on the stove until very hot. Pour it over the chocolate in a bowl.
Let it sit for 2 minutes to melt the chocolate. (4)Stir until smooth. Refrigerate to slightly cool the mixture, about 30 minutes, .
(5)With a hand mixer, whip on medium-high speed until fluffy and lighter in color, about 3 minutes.
(6) Spread the whipped ganache evenly on the cooled brownie. Decorate with rainbow sprinkles.
How to serve and store
Let the birthday brownies set for at least an hour in the fridge before cutting. Refrigerate leftovers and eat within five to seven days.
If wrapped properly, you can freeze them for up to three months. Let them thaw in the fridge or on the counter.
Frequently asked questions
Eggs at room temperature blend evenly 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. Cool the ganache first to prevent this.
You only need to whip it for one to three minutes until it is fluffy and lighter in color. If it has turned grainy, reheat in a double boiler and start over.
More about brownies
If you'd like to know more, here are frequently asked questions on brownies including extra tips, troubleshooting, and more.
Watch how I make it here
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📖 Recipe
Birthday Brownies From Brownie Mix
Equipment
- 8x8-inch pan
Ingredients
For the brownie layer (see package instructions)
- 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 chocolate ganache frosting
- 4 ounces dark chocolate - bittersweet or semisweet (113 grams) chips or finely chopped
- ¾ cup heavy cream (177 grams) hot
- 2 tablespoons rainbow sprinkles (20 grams)
Instructions
- Pour the hot cream over the chocolate in a bowl. Let it sit for 2 minutes to melt the chocolate. Stir until smooth. Refrigerate to slightly cool the mixture, about 30 minutes.
- Spread the whipped ganache evenly on the cooled brownie. Decorate with rainbow sprinkles.
- Refrigerate for at least an hour before cutting.
Video
Notes
- Bring the eggs to room temperature and lightly beat them to ensure they get incorporated well without overmixing.
- Grease and line the pan with parchment paper so the brownies will not stick and come out easily.
- Check the brownies two minutes before they should be done. Test with a toothpick — it should come out with several separate crumbs for fudgy brownies and less for cakey.
- Cool the brownies before slicing. Refrigerating them improves their texture.
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