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stack of birthday cake brownies with more brownies behind

Birthday Cake Brownies

Birthday cake brownies are a delicious treat for anyone who loves chocolate and sprinkles!

Course Dessert
Cuisine American
Prep Time 20 minutes
Cook Time 45 minutes
Total Time 1 hour 5 minutes
Servings 9
Author Kelsie



  • 8 ounces full fat cream cheese at room temperature
  • 1 large egg + 1 large egg yolk
  • 1/2 cup white or yellow cake mix powder
  • 1/4 cup powdered sugar
  • 1 teaspoon vanilla
  • 1/4 teaspoon salt
  • 6 tablespoons rainbow jimmies


  • 3/4 cup unsalted butter
  • 3 ounces unsweetened chocolate finely chopped
  • 1 1/2 cups granulated sugar
  • 3 large eggs
  • 1 1/2 teaspoons vanilla extract
  • 1/2 cup all-purpose flour
  • 1/4 cup white or yellow cake mix powder
  • 1/2 teaspoon salt



  1. Place the cream cheese, egg, egg yolk, cake mix, sugar, vanilla, and salt in a medium bowl. Beat with an electric mixer until very smooth, scraping down the sides of the bowl as needed. Fold in the jimmies. Set aside.


  1. Preheat the oven to 350 degrees. Line an 8-inch square baking dish with foil. Spray the foil with cooking spray and set pan aside.
  2. Combine the butter and unsweetened chocolate in a microwave-safe bowl and heat in 30-second intervals, stirring after each interval, until melted and smooth. (Or you can do this in the top of a double boiler set over barely simmering water.) Set the mixture aside to cool for 5 minutes.
  3. Combine the sugar, eggs, and vanilla, in a large mixing bowl. Stir vigorously with a rubber spatula until well combined. Stir in the chocolate mixture.
  4. Add the flour, cake mix, and salt and mix until just combined.
  5. Pour half of the brownie batter into the prepared pan. Use an offset spatula to spread the filling into an even layer over the brownie batter.
  6. Dollop the remaining brownie batter over the filling, then carefully spread it out. Use a butter knife to swirl the batter and the filling together (don’t over-swirl).
  7. Bake 45 to 50 minutes, until the brownies have just begun to pull away from the pan at the edges and the center is still a little jiggly.
  8. Cool completely, then slice and serve. (The brownies are easier to slice neatly if you chill the overnight first.)
  9. Uneaten brownies can be stored in the fridge, tightly wrapped, for up to 3 days or in the freezer for up to 3 months.

Recipe Video

Recipe Notes

You can use either white or yellow cake mix in these brownies but using white cake mix allows the sprinkles to pop a little more.

There’s a lot of batter so be sure your baking pan is at least 2 inches tall. If it isn’t, the batter might puff up and fall over the edges in the oven.