If you like my Rice Krispie Treats with Marshmallow Fluff, you will love these brownies!
These brownies are just plain fun. You get a rich, fudgy chocolate brownie layer with a soft, sprinkle-loaded cookie cake on top, and both layers bake at the same time in the same pan. The bars come out thick and chewy around the edges with a softer center, and you can see rainbow sprinkles in every slice.
They feel like a classic birthday party treat in bar form, the kind of thing kids love and adults will happily grab, too. They’re easy to pack up for school parties, potlucks, or family birthdays, and they look fun on any dessert table. Cut them into bars, add a few candles or a scoop of ice cream, and you’re set.
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💛 Why you’ll love this recipe
- Ready for the oven in just 15 minutes.
- Fun colors from the sprinkles without needing frosting.
- Two layers bake at the same time in the same pan.
- Slices hold up well, so they’re easy to make ahead for parties or gifting.
➡️ Ingredients you’ll need
⏲ How to make this birthday brownies recipe
👉 Easy ingredient swaps
- Butter: Use unsalted butter, then add the salt as listed in the recipe instructions.
- Sprinkles: Pastel or holiday sprinkles also work if you want a seasonal version.
- Chocolate: Chopped baking chocolate works the same way, if that’s what you have.
✨ Variations
- Extra Chocolate: Add a handful of chocolate chips to the brownie layer for more richness.
- Oreos: Fold chopped Oreos into the cookie layer or press a layer of Oreos on top before baking.
- M&M Topping: Sprinkle M&Ms over the batter before it goes in the oven for extra color and crunch.
- Vanilla Buttercream: Let the bars cool completely, then spread a thin layer of vanilla buttercream over the top before slicing.
〰️ How to serve
- Ice cream — Vanilla ice cream, birthday cake ice cream, or anything with sprinkles.
- Fruit — Fresh berries or sliced strawberries.
- Drinks — Milk, hot chocolate, or coffee for a simple pairing.
💬 FAQs
Can I make these ahead of time?
Yes. Bake them, let them cool completely, and store at room temperature for up to 3 days. They keep their chewy texture, so they work well made the day before a party.
How should these be stored?
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.
Can I freeze these?
Yes. 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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Birthday Brownies
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 8×8-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.
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