Funfetti cookies (galletas de cumpleaños) are soft, chewy vanilla sugar cookies filled with colorful rainbow sprinkles, designed to taste like birthday cake.

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This funfetti cookie recipe uses all-purpose flour with a little cornstarch, plus sour cream, butter, and vanilla, to create soft, birthday-cake cookies with rainbow sprinkles.
They're easy to make and perfect for parties, celebrations, or a festive homemade dessert.
Ingredients You'll Need
Note: Full ingredients and amounts are listed in the recipe card below.
- Unsalted butter: Provides fat for a soft cookie texture and forms the base of the buttercream frosting.
- Granulated sugar: Sweetens the cookies and supports structure.
- Confectioners' sugar: Softens the cookie crumb and sweetens the frosting.
- Egg yolk: Adds richness and helps bind the dough.
- Sour cream: Keeps cookies soft and tender.
- Vanilla extract & clear vanilla: Provide classic birthday-cake flavor.
- All-purpose flour: Forms the cookie structure.
- Cornstarch (optional): Creates a softer texture in the cookies.
- Baking powder: Helps cookies rise slightly.
- Salt: Balances sweetness.
- Rainbow sprinkles: Add color and texture.
- White chocolate: Adds structure and flavor to the frosting.
How to Make Funfetti Cookies
Note: Full instructions are provided in the recipe card below.
- For the cookies: Preheat the oven to 350°F (175°C) and line two baking sheets with parchment paper.
- In the bowl of a stand mixer fitted with the paddle attachment, beat the butter, granulated sugar, powdered sugar, baking powder, salt, and both vanilla on medium speed until the mixture is evenly blended and forms a grainy paste, about 2-3 minutes.
- Scrape down the bowl. Add the egg yolk and mix until combined (about 30 seconds). Then add the sour cream and beat until the mixture is fluffy.
- In a separate bowl, whisk together the flour and cornstarch (if using). Add the dry ingredients to the mixer and mix on low speed until most of the flour is incorporated. Add the sprinkles and mix just until combined.
- Portion the dough into rounded tablespoon-size pieces, placing about 10 cookies per baking sheet. Roll into balls and gently press them to about ¾-inch thickness.
- Bake one sheet at a time for 15-17 minutes, until the edges are lightly golden and the centers are set. Let the cookies cool completely on the baking sheets set over wire racks.
- For the white chocolate buttercream frosting: Place the chopped white chocolate in a microwave-safe bowl and heat in short bursts, stirring after each burst, until fully melted and smooth. Set aside.
- Beat the butter in a stand mixer until creamy and glossy, about 2-3 minutes. Add the powdered sugar, both vanilla, salt, and milk. Mix on low speed until combined, then increase to high speed and beat for about 1 minute.
- Scrape down the bowl, add the melted white chocolate, and mix on low speed until incorporated. Increase to medium speed and beat until smooth and fluffy, about 1 minute.
- Transfer the white chocolate buttercream to a piping bag fitted with a star tip and pipe a rosette or star onto each cookie. You can also spread the frosting with a small spatula. Finish with rainbow sprinkles.

Hint: Chill the funfetti cookies before storing to firm the chocolate in the buttercream and make them easier to stack.
Storage, Make Ahead, & Freezing
Storage: Store the Funfetti cookies in an airtight container for up to 3 days.
Make Ahead: You can bake the cookies a day in advance and frost them before serving.
Freezing: Freeze the cookies without frosting in an airtight container for up to 2 months. Thaw, then frost before serving.

Camila's Tips & Variations
- Cookies spreading too much: Chill the dough for 15-20 minutes before baking.
- Frosting too soft: Chill briefly to firm the white chocolate buttercream.
- Cookies browning too fast: Bake on the center rack and one sheet at a time.
- Extracts: I love combining pure vanilla extract with clear vanilla or cake batter extract for a stronger birthday-cake flavor.

Frequently Asked Questions
Can I make birthday cookies without sour cream?
Yes. Use plain yogurt instead to keep the cookies soft and moist.
Why did my cookies spread too much?
Butter that is too warm causes spreading. Chill the dough before baking.
Can I skip the cornstarch?
Yes. The cookies will still bake properly, but will be slightly less soft.
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Recipe
Funfetti Cookies

Ingredients
Cookies:
- 190 grams all-purpose flour
- 1 tablespoon cornstarch , optional
- 113 g unsalted butter , softened
- 35 g confectioners' sugar
- 115 g granulated sugar
- 2 teaspoons baking powder
- ½ teaspoon kosher salt
- 1 tablespoon pure vanilla extract
- 1 large egg yolk
- 40 grams sour cream or plain yogurt
- 2 tablespoons rainbow sprinkles
Frosting:
- 57 grams white chocolate , finely chopped
- 113 g unsalted butter , softened
- 115 g confectioners' sugar
- ½ teaspoon pure vanilla extract
- ½ teaspoon clear vanilla
- ⅛ teaspoon kosher salt
- 1 teaspoon milk , heavy cream, or water
- ¼ cup rainbow sprinkles
Instructions
- For the cookies: Preheat the oven to 350°F (175°C) and line two baking sheets with parchment paper.
- In the bowl of a stand mixer fitted with the paddle attachment, beat the butter, granulated sugar, powdered sugar, baking powder, salt, and both vanilla on medium speed until the mixture is evenly blended and forms a grainy paste, about 2-3 minutes.
- Scrape down the bowl. Add the egg yolk and mix until combined (about 30 seconds). Then add the sour cream and beat until the mixture is fluffy.
- In a separate bowl, whisk together the flour and cornstarch (if using). Add the dry ingredients to the mixer and mix on low speed until most of the flour is incorporated. Add the sprinkles and mix just until combined.
- Portion the dough into rounded tablespoon-size pieces, placing about 10 cookies per baking sheet. Roll into balls and gently press them to about ¾-inch thickness.
- Bake one sheet at a time for 15-17 minutes, until the edges are lightly golden and the centers are set. Let the cookies cool completely on the baking sheets set over wire racks.
- For the frosting: Place the chopped white chocolate in a microwave-safe bowl and heat in short bursts, stirring after each burst, until fully melted and smooth. Set aside.
- Beat the butter in a stand mixer until creamy and glossy, about 2-3 minutes. Add the powdered sugar, both vanilla, salt, and milk. Mix on low speed until combined, then increase to high speed and beat for about 1 minute.
- Scrape down the bowl, add the melted white chocolate, and mix on low speed until incorporated. Increase to medium speed and beat until smooth and fluffy, about 1 minute.
- Transfer the buttercream to a piping bag fitted with a star tip and pipe a rosette or star onto each cookie. You can also spread the frosting with a small spatula. Finish with rainbow sprinkles.
Notes
Nutrition
Nutrition Disclaimer: The nutritional information provided is an estimate, calculated using standard data sources. Actual values may vary based on ingredient brands, preparation methods, and portion sizes. This information is for general reference only and should not be considered a substitute for professional dietary advice.








