Birthday Brownies

A square piece of sprinkled birthday cake with a lit blue candle in the center, served on a white plate with colorful sprinkles.

These Birthday Brownies are perfect for birthdays, school parties, potlucks, or any time you want a fun dessert that feels like a celebration! They’re made with a rich, fudgy chocolate brownie layer topped with a soft, sprinkle-packed cookie cake, and everything bakes together in one pan. You end up with bars that are chewy around the edges, softer in the center, and loaded with chocolate and rainbow sprinkles in every bite.

Prep Time15

Cook Time25

Total Time40

Course: Dessert

Cuisine: American

Keyword: birthday brownies

Servings: bars

Calories: 412kcal

Ingredients

Cookie Cake Batter

½ cup salted butter melted then cooled slightly
½ cup light brown sugar packed
⅓ cup granulated sugar
2 large eggs room temperature
2 teaspoons vanilla extract
1 ¼ cup all-purpose flour
¼ teaspoon salt
¼ teaspoon baking powder
¼ cup rainbow sprinkles

Brownie Batter

4 Tablespoons salted butter
¼ cup semi-sweet chocolate chips
6 Tablespoons granulated sugar
1 egg
¼ cup all-purpose flour
¼ cup unsweetened cocoa powder
1 teaspoon vanilla extract
⅛ teaspoon salt

Topping

3 Tablespoons sprinkles

Instructions

Prep Pan: Preheat oven to 350 °F. Line 8x8-inch metal baking pan with parchment paper, leaving an overhang on at least two sides for easy lifting. Spray parchment paper lightly with cooking spray.
Cookie Cake Batter: In large bowl, whisk ½ cup salted butter (melted and cooled), ½ cup light brown sugar, ⅓ cup granulated sugar until combined. Whisk in 2 large eggs (room temperature) and 2 teaspoons vanilla extract until smooth, about 2 minutes.
Add Dry Ingredients: Add 1 ¼ cup all-purpose flour, ¼ teaspoon salt, and ¼ teaspoon baking powder (if using unsalted butter, add extra ¼ teaspoon salt). Stir until combined, then fold in ¼ cup rainbow sprinkles. Batter should be thicker than cake batter but looser than cookie dough. Spread two-thirds of batter into prepared pan right away so it doesn’t thicken too much.
Brownie Batter: In microwave-safe bowl, melt 4 Tablespoons salted butter and ¼ cup semi-sweet chocolate chips on 50% power for about 1 minute. Stir until smooth, then let cool a few minutes so it doesn’t cook egg.
Add Remaining Ingredients: Whisk in 6 Tablespoons granulated sugar, 1 egg (room temperature), ¼ cup all-purpose flour, ¼ cup unsweetened cocoa powder, 1 teaspoon vanilla extract, and ⅛ teaspoon salt until just combined; don’t overmix. (If using unsalted butter, add extra ⅛ teaspoon salt here.)
Layer Batters: Pour brownie batter over cookie layer and smooth out with a rubber spatula. Dollop remaining cookie batter on top in small spoonfuls and lightly spread with the spatula. Sprinkle 3 Tablespoons sprinkles over top.
Bake: Bake 24-29 minutes, or until top looks set and cookie portions are lightly golden. Center should no longer look wet, and shiny top should stay intact when you gently shake pan. A toothpick will not come out clean with this recipe; use set, shiny top as doneness guide.
Cool then Slice: Cool brownies completely on wire rack. Lift out using parchment overhang and cut into 9 large squares or smaller pieces.

Notes

To Make In Advance: Bake, cool fully, and store them at room temperature for up to 3 days. They hold their texture well, so they’re great for making the day before a party.

Room Temp and Fridge Storage: Store leftover brownies in an airtight container at room temperature for up to 3 days, or in the fridge for up to 5 days. The cookie layer stays soft and the brownie keeps its chewy texture.

Freezer Storage: Wrap individual slices tightly in plastic wrap, place them in a freezer bag, and freeze for up to 2 months. Thaw at room temperature, or warm briefly in the microwave.

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