Drop Everything and Make These Funfetti Blondies

Cake Batter Blondie Bars

Adapted from Dessert Mashups: Tasty Two-in-One Treats Including Sconuts, S'morescake, Chocolate Chip Cookie Pie and Many More [1] by Dorothy Kern

For the blondies:
1 teaspoon baking powder
1 teaspoon kosher salt
2 cups (10 ounces) all-purpose flour
1/2 cup (3 1/2 ounces) granulated sugar
1 cup (8 ounces) packed brown sugar
1 stick (4 ounces) unsalted butter, at room temperature
2 large eggs
1 teaspoon vanilla extract
1 teaspoon butter extract [2]
1/2 cup rainbow sprinkles

For the frosting:
1 stick (4 ounces) unsalted butter, at room temperature
1/4 teaspoon kosher salt
1 1/2 cups (6 ounces) powdered sugar, sifted
1 teaspoon vanilla extract
1 teaspoon whole milk, optional
Sprinkles, for garnish

Make the blondies: Preheat the oven to 350°F. Spray a 9-by-13-inch Pyrex or ceramic dish with nonstick cooking spray.
In a medium bowl, whisk together the baking powder, salt, and flour.
In the bowl of a stand mixer fitted with the paddle attachment, cream together the granulated sugar, brown sugar, and butter. Add the eggs, vanilla, and butter extract, and beat until combined. Add the dry ingredients and mix until combined. Stir in the sprinkles.
Press the dough into the prepared pan. (The dough will be sticky; spray your hands with cooking spray to keep it from sticking to you.) Bake for 22 to 24 minutes. They will be slightly golden but still have the slightest jiggle in the center. They'll set as they cool. Cool completely before frosting.
Make the frosting: Using an electric hand mixer or stand mixer fitted with the paddle attachment, beat the butter and salt until smooth. Slowly add in the powdered sugar, and mix until smooth. Add the vanilla extract, and the milk if the frosting looks a little dry, and mix until smooth.
Frost the bars using an offset spatula. Top with sprinkles, and cut into bars. Store covered at room temperature or in the refrigerator. Best eaten at room temperature within 5 days.