Preheat your oven to 350°F (175°C). This ensures that your blondies bake evenly.
Line a 9x13-inch baking pan with parchment paper, leaving some overhang on the sides to help with removal later. Grease the parchment for easy release.
In a medium bowl, whisk together the all-purpose flour and salt. Set this mixture aside.
In a large mixing bowl, combine the melted butter, light brown sugar, and granulated sugar. Whisk until well blended. Add in the eggs and vanilla extract, mixing until smooth.
Gradually add the flour mixture to the wet ingredients, stirring until just combined. Be careful not to overmix—this keeps your blondies chewy.
Pour the batter into the prepared baking pan, spreading it evenly with a spatula. Bake for about 25-30 minutes, or until a toothpick inserted in the center comes out clean. Let the blondies cool in the pan before frosting.
In a mixing bowl, beat together 1 stick of unsalted butter, 3 cups of confectioners' sugar, 3/4 cup cocoa powder, 4 tablespoons of milk, 1/4 teaspoon salt, and 1 teaspoon vanilla extract until smooth and creamy.
Once the blondies are completely cool, spread the chocolate frosting evenly over the top using a spatula.
In another bowl, beat together 1 stick of unsalted butter, 3 1/2 cups of confectioners' sugar, 4 tablespoons of milk, 1/4 teaspoon salt, and 2 teaspoons vanilla extract until light and fluffy.
Spread the second layer of frosting evenly over the chocolate frosting layer, creating a beautiful two-tiered effect.
Top the frosted blondies with colorful sprinkles, adding a festive touch.
Refrigerate the blondies for at least 30 minutes to set the frosting. Once firm, lift the blondies out of the pan using the parchment paper, and cut them into bite-sized squares.
