Take your cookie-bar love up a notch with these Birthday Cake Blondies. Soft and chewy, they deliver classic birthday-cake flavor with plenty of rainbow sprinkles and white chocolate for extra sweetness. They’re simple to make and perfect for parties, bake sales, or a colorful weeknight treat.
If you enjoy these, try pairing them with a batch of birthday sugar cookies for a full celebration spread.
These birthday blondies have a tender, cake-like crumb with the chewy bite you want from a bar cookie. The recipe highlights vanilla and a touch of almond and butter extracts to mimic that nostalgic birthday-cake aroma. Fold in white chocolate chips and colorful sprinkles for a fun, festive finish. They bake quickly and stay moist, making them ideal for making ahead and transporting to an event.
The instructions below are straightforward and use common pantry ingredients. Read through the notes and tips to customize flavors and toppings, and to learn the best way to store leftovers.
Ingredients
- Butter – Use unsalted for control; add a pinch of salt if needed.
- Granulated sugar
- Brown sugar – Adds moisture and a hint of caramel color.
- Egg – Binds the batter and contributes to structure.
- Vanilla extract – Main flavor.
- Almond extract – A small amount brightens the cake flavor.
- Butter extract – Optional, for a richer buttery note.
- All-purpose flour – The base of the batter.
- Baking soda – For a light texture.
- Salt – Balances sweetness.
- White chocolate chips – Mixed in and for the topping.
- Rainbow sprinkles – Stirred in and scattered on top for color.
- Coconut oil – A small amount to thin the melted white chocolate for drizzling.
See recipe section below for exact quantities and topping amounts.
How to Make Birthday Cake Blondies
Preheat the oven to 350°F (175°C). Line a 9 x 13-inch baking pan with parchment paper or lightly spray with cooking spray.
Step 1: In a large bowl, cream together the softened butter, granulated sugar, and brown sugar until the mixture is light and smooth.
Step 2: Beat in the egg, vanilla, almond extract, and butter extract until fully combined.
Step 3: Add half of the flour, the baking soda, and salt. Mix until smooth, then add the remaining flour and mix just until incorporated. Avoid overmixing.
Step 4: Fold in the white chocolate chips and most of the sprinkles, reserving a little to sprinkle on top after baking.
Step 5: Spread the batter evenly into the prepared baking pan and smooth the top.
Step 6: Bake for about 18–20 minutes, or until the center no longer jiggles and the edges are lightly golden. Allow the blondies to cool completely in the pan.
Step 7 (Topping): Melt the topping white chocolate chips with the coconut oil in short bursts in the microwave (about 15 seconds at a time), stirring between bursts until smooth. Drizzle or spread the melted chocolate over the cooled blondies, then scatter the remaining sprinkles on top. Chill briefly until the chocolate sets, about 10 minutes, before slicing.
Top Tip
Make sure the blondies are completely cool before adding the melted chocolate and sprinkles. If the bars are warm, the topping will melt in and won’t set properly.
Substitutions
- Frosting: If you prefer not to melt chocolate, a store-bought or homemade frosting can replace the white chocolate topping for a different texture and flavor.
Variations
- Toppings: Try crushed golden Oreos, chopped nuts, or a mix of colored candies for a new twist.
- Seasonal: Swap sprinkles to match holidays—red and green for Christmas, orange and black for Halloween, or pink and red for Valentine’s Day.
Equipment
You’ll only need basic kitchen tools: an electric mixer (or a sturdy whisk), a large mixing bowl, measuring cups and spoons, and a 9 x 13-inch baking pan lined with parchment or sprayed with nonstick spray.
Storage
Store cooled blondies in an airtight container at room temperature for a few days or refrigerate for longer freshness. For longer storage, freeze individual portions wrapped tightly and thaw as needed.
Common Question
Why add coconut oil to melted white chocolate? A small amount of coconut oil thins the melted white chocolate so it’s easier to drizzle or spread and sets with a smoother finish.
Related
Try other blondie and brownie variations for more party-worthy bars: maple pecan, lemon blondies, double chocolate brownies, or blueberry blondies—each offers a different flavor profile while keeping the same satisfying bar format.
Recipe
Birthday Cake Blondies — Makes 16 bars
- 1 cup butter, softened
- 1/2 cup granulated sugar
- 1/4 cup brown sugar
- 1 egg
- 1/2 tsp vanilla extract
- 1/2 tsp almond extract
- 1/2 tsp butter extract (optional)
- 1 1/2 cups all-purpose flour
- 1 tsp baking soda
- 1/2 tsp salt
- 1/2 cup white chocolate chips (in batter)
- 1/2 cup rainbow sprinkles (in batter)
Topping: 1/2 cup white chocolate chips, 1/2 tsp coconut oil, 2 Tbsp sprinkles.
Instructions (Summary)
- Preheat oven to 350°F. Line a 9 x 13 pan.
- Cream butter and sugars. Add egg and extracts.
- Mix in half the flour, baking soda, and salt. Add remaining flour and stir just until combined.
- Fold in chips and sprinkles. Spread into pan.
- Bake 18–20 minutes until set. Cool completely.
- Melt topping chips with coconut oil, spread or drizzle, and add sprinkles. Chill until set and slice.
Enjoy these colorful, chewy Birthday Cake Blondies at your next celebration—simple to make and impossible not to smile at!