Experience the ultimate birthday dessert mashup with these epic Birthday Cake Brownies–soft and chewy funfetti cookie bars topped with a rich fudgy brownie layer, all loaded with colorful sprinkles and mini chocolate chips for serious celebration vibes!

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Today I'm sharing the dessert that is basically two desserts in one! If you can't decide between a cookie recipe or a brownie recipe (the eternal struggle, am I right?), this recipe is about to become your new obsession!
The bottom layer is this ultra-soft, chewy funfetti cookie bar that's packed with rainbow sprinkles and has that classic birthday cake flavor we all dream about. But then, on top of that is a decadent layer of rich, fudgy brownie studded with mini chocolate chips that adds the perfect balance to all that vanilla goodness.
I've been on such a birthday cake kick lately with my birthday cake blondies and these stuffed birthday cake cookies, but this might be my favorite creation yet!
Whether you're celebrating an actual birthday or just making a random Wednesday feel special, these two-layer birthday brownies are guaranteed to bring all the party vibes!
Why You'll Love This Recipe
- PERFECT Birthday Cake Alternative! All the celebration vibes without the fuss of a cake! These two-layer brownies slice beautifully, travel well, and can be eaten with your hands, making them the ultimate party dessert when you want something more exciting than regular cake!
- Quick & Easy 45-Minute Dessert! From mixing bowl to mouth in less than an hour! Unlike layer cakes that need cooling and decorating time, these come together in two simple batters and bake at once - perfect for last-minute celebrations or sudden sweet cravings!
- 100% From-Scratch Flavor! No box mixes here! Made completely from scratch for that authentic vanilla-forward funfetti layer and deeply rich chocolate brownie top that just hits different! Real ingredients = REAL flavor that your taste buds will notice immediately!
Ingredients Notes
- Egg + Egg Yolk: This combo is literally the SECRET to the cookie bar layer! The extra yolk adds richness and helps create that perfect chewy texture. Make sure they're room temp for the best incorporation into your batter!
- Vanilla: Don't skimp on this! High-quality pure vanilla extract gives that classic birthday cake flavor to the funfetti layer. I splurge on the good stuff here.
- Butter: Use unsalted butter to control the amount of salt that goes into the recipe. Melting the butter contributes to the chewy texture of the cookie and brownie layers.
- Sprinkles: Rainbow sprinkles are so fun and fitting for birthdays! Stick with sprinkles (jimmies). Nonpareils might bleed into your cookie dough during baking.
- Chocolate Bar: Chop up a good quality semi-sweet chocolate bar for the brownie layer instead of using chips! Chocolate chips have stabilizers that prevent them from melting completely, but a chopped bar gives you that super fudgy texture and richer chocolate flavor that makes these brownies absolutely next level!
- Cocoa powder: Using unsweetened cocoa powder adds a rich flavor to the brownie layer. If you have Dutch-processed cocoa powder on hand, you can use that instead.
How to Make This Recipe (step-by-step)
Whisk dry and wet ingredients separately. Whisk together the cookie batter dry ingredients and set aside. In a separate bowl, whisk together the sugar, egg, egg yolk, and vanilla until the mixture becomes light and creamy. Add the melted butter and combine.
Add dry ingredients. Fold the dry ingredients and sprinkles into the butter mixture until combined.
Prepare brownie batter. Melt the chocolate and butter together until completely smooth. Whisk the sugar and egg together constantly for 2-3 minutes until pale in color.
Combine chocolate and egg mixtures. Add the melted chocolate to the sugar and egg mixture and combine.
Add dry ingredients. Gently fold in the dry ingredients along with the mini chocolate chips.
Add cookie batter to pan. Scoop the cookie batter into a parchment-lined 8x8-inch square pan, leaving spaces between each scoop.
Add brownie batter. Pour the brownie batter into the pan to fill the gaps and spread it into an even layer with an offset spatula. Sprinkle with the sprinkles and mini chocolate chips and bake for 25 to 28 minutes.
Note: Whisking the eggs and sugar together until thickened and a pale yellow color is referred to as the “ribbon stage”. The mixture will fall from the whisk like ribbons. This technique creates taller and creamier brownies with a shiny crust.
Expert Baking Tips
- Scale Your Ingredients: I can't stress enough the importance of using a kitchen scale! Measuring flour and cocoa powder by weight instead of cups makes a huge difference in these brownies. Too much flour = a more cakey brownie (and less fudgy), and nobody wants that!
- Use a Light Colored Aluminium Pan: Dark pans are the enemy of perfect brownies! They absorb too much heat, which leads to overdone edges and a cakey texture we're trying to avoid. An 8x8 pan will give you that perfect even bake with the fudgy center.
- Line Your Pan with Parchment Paper: Don't just spray the pan and hope for the best. Line the pan with parchment paper with overhang on all sides so you can lift the entire slab out after cooling.
- Cool COMPLETELY Before Slicing: I know it's torture, but these two-layer brownies need to cool fully before cutting. Patience gets you those perfect, clean-cut squares with distinct layers.
Recipe Substitutions
As a trained pastry chef I’ve learned that it’s not always simple to make substitutions to recipes. But here are two substitutions that can easily be made to your brownies.
- Substitute brown sugar for the granulated sugar in the brownie batter for an even fudgier brownie.
- For this recipe, Dutch-process cocoa powder can be substituted for unsweetened (natural) cocoa powder. This substitution will result in darker brownies with an even more intense chocolate flavor.
Recipe Variations
Birthday cake brownies are such a festive dessert to serve. Here are some ideas for tweaking this recipe to your preferences and how to serve it!
- Add Oreos: Press whole Golden Oreos into the funfetti layer before adding the brownie batter on top! The cookies soften slightly during baking but keep their structure, creating these incredible vanilla cookie pockets throughout.
- Serve A La Mode: Warm these squares up for 15 seconds in the microwave and top with a scoop of vanilla ice cream.
- Brown that Butter: If you want to get fancy with it, brown the butter for the funfetti layer. This adds this incredible, nutty, caramelized flavor.
Storage Tips
To store. These birthday cake brownies stay perfectly soft and chewy at room temperature for up to 3 days! Just store them in an airtight container. These will last up to 1 week in the fridge.
To freeze. Store leftovers in an airtight container or freezer-safe bag and freeze for up to 3 months. When ready to enjoy, thaw in the refrigerator overnight.
FAQ
Yes, you can bake a double batch of these brownies in a 9x13-inch rectangular baking pan. Increase the time slightly to account for the extra batter.
Once the edges are visibly set and pulling away slightly from the sides of the pan, the brownies are done! You'll also see the top has that shiny, crackly appearance and feels set to a light touch.
Fudgy brownies have a more dense and chewy texture. They are rich and sometimes even gooey. Fudgy brownies typically use more butter which is melted with the chocolate. Cakey brownies are lighter and more cake-like and are typically made with creaming the butter and sugar.
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I hope you enjoy this recipe and that it becomes a family favorite! I would love for you to leave me a review and star rating below to let me know how you liked it! And please tag me on social @thesweetoccasion!
Easy & Fudgy Birthday Cake Brownies
- Total Time: 45 minutes
- Yield: 16 bars 1x
Description
Experience the ultimate birthday dessert mashup with these epic Birthday Cake Brownies–soft and chewy funfetti cookie bars topped with a rich fudgy brownie layer, all loaded with colorful sprinkles and mini chocolate chips for serious celebration vibes!
Ingredients
For the Cookie Batter
- 210 g (1 ½ cups) all-purpose flour
- ¾ teaspoon baking soda
- ¼ teaspoon salt
- 165 g (¾ cup) granulated sugar
- 1 large egg
- 1 large egg yolk
- 1 teaspoon vanilla extract
- 113 g (½ cup) unsalted butter, melted
- 50 g (⅓ cup) rainbow sprinkles, plus more for sprinkling
For the Brownie Batter
- 55 g (4 tablespoons) unsalted butter
- 55 g (2 ounces) semi-sweet chocolate bar, chopped
- 75 g (⅓ cup) granulated sugar
- 1 large egg
- 1 teaspoon vanilla extract
- 35 g (¼ cup) all-purpose flour
- 20 g (¼ cup) unsweetened cocoa powder, sifted
- 2 teaspoons cornstarch
- ¼ teaspoon salt
- 60 g (⅓ cup) mini chocolate chips, plus more for sprinkling
Instructions
For the Cookie Batter
- Preheat the oven to 350°F/177°C. Line an 8x8-inch square baking pan with parchment paper to hang over the edges (to remove the brownies easily).
- In a medium bowl, whisk together the flour, baking soda and salt.
- In a large bowl, whisk together the sugar, egg, egg yolk and vanilla until light and creamy, about 1 minute. Slowly pour in the melted butter while whisking until combined.
- Gently fold in the flour mixture and sprinkles until just combined.
For the Brownie Batter
- In a small microwave-safe bowl, microwave the butter and chopped chocolate for 30 seconds. Mix together and continue to microwave for 15-second intervals until melted and smooth.
- In a large bowl, whisk together the sugar and egg for 2-3 minutes or until light and smooth. Slowly pour in the chocolate mixture and vanilla while whisking to combine.
- Using a rubber spatula, gently fold in the flour, cocoa powder, cornstarch and salt until just combined. Do not overmix. Fold in the chocolate chips.
- Drop large scoops of cookie batter into the prepared pan and slightly flatten. Fill in the remaining space with the brownie batter and spread into an even layer. Sprinkle with rainbow sprinkles and mini chocolate chips.
- Bake for 25 to 28 minutes or until a toothpick inserted in the center comes out mostly clean with some moist crumbs. Allow the brownies to cool completely in the pan before slicing.
Notes
- Storage: Store in an airtight container for up to 3 days at room temperature or 1 week in the refrigerator.
- Freeze: Store leftovers in an airtight container or freezer-safe bag and freeze for up to 3 months. When ready to enjoy, thaw in the refrigerator overnight.
- Prep Time: 20 minutes
- Cook Time: 25 minutes
- Category: Brownies & Bar
Georgia says
This was a hit in our family! I'll be making this again soon. Next time I will add some white chocolate chips in the funfetti layer as well (similar to your birthday cake blondies recipe.)
Maria Pagiotas says
Hi Georgia! So happy you loved this recipe! That'll be delicious too! The blondies are my husband's favorite 🙂
Kristen says
What a fun dessert to make! My kids helped bake these and loved the results (as did my husband and I!). Next time I will try your suggestion and add a layer of crushed oreos 🙂
Maria says
Hi Kristen! Thank you for sharing! It is a fun recipe to make with kids! The Oreos add a fun surprise 🙂 Happy Baking!
Joanna says
Love how easy this recipe is! I made it for my son's birthday party (doubled the recipe) and it was a hit with the kids and adults!
Maria says
Hi Joanna! So happy you loved this recipe. It's always fun for parties 🙂