Soft Sugar Cookie Bars are frosted with a thick, fluffy layer of buttercream and loaded with funfetti sprinkles for an easy gluten-free dessert bar recipe!
Preheat the oven to 350ºF. Spray a 9X13 baking pan with cooking spray and set aside.
In a large bowl cream together the butter and sugar together until very pale, light, and fluffy, about 3 minutes. Beat in egg, yolk, and vanilla until well mixed.
½ cup unsalted butter, ¾ cup granulated sugar, 1 egg + 1 egg yolk, 2 teaspoons vanilla extract
To the bowl add the salt, baking powder, baking soda, and cornstarch. Mix well. Gradually add in the flour and beat on low speed until just combined. The dough will be very thick. Stir in sprinkles or mix on low speed.
¼ teaspoon salt, 1 teaspoon baking powder, ½ teaspoon baking soda, 1 ½ teaspoons cornstarch, 1 ½ cups gluten free all-purpose flour
Spread the cookie mixture in the prepared baking pan. Bake for 23-25 minutes (about 2-3 minutes longer if using gluten free flour) until a toothpick inserted in middle comes clean. The bars will be lightly browned. Allow the bars to cool completely on wire rack before frosting.
Buttercream Frosting:
In a large bowl beat the butter until light and creamy. Add the powder sugar, heavy cream, vanilla, and pinch of salt. Gradually mix on low speed until well mixed.
½ cup rainbow sprinkles (NOT nonpareils), ¾ cup unsalted butter, 2 cups powdered sugar, 6 tablespoons heavy cream, 1 teaspoon vanilla extract, ⅛ teaspoon salt
Increase mixer to high and beat until very light and fluffy, about 5-7 minutes. TIP: Beating for a long time is what makes this frosting extremely fluffy. Mix in food coloring, if using.
food coloring
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Notes
Baking in an 8X8 panFor a thicker, soft bar leave the ingredient amounts as is and bake for 25 minutes. Alternatively, halve the bar and frosting ingredients and bake for 5-10 minutes less.
Alternative FrostingsSome home bakers prefer the taste of sugar cookie bars with cream cheese frosting. Halve the cream cheese frosting recipe from red velvet cake recipe or, for a different flavor, substitute chocolate buttercream frosting.
Storing / FreezingCover any leftovers securely with plastic wrap and leave at room temperature up to 3 days. They may also be frozen, covered securely, up to 3 months. Alternatively, wrap individually and enjoy as needed!