Birthday Cake Cookie Bars
Heat oven to 350 degrees. Line a 13 x 9 x 2-inch baking pan with foil.Advertisement
In a stand mixer, beat butter until smooth. Beat in sugar, baking powder and salt.
Beat in eggs, one at a time, scraping down sides of bowl after each. Beat in vanilla.
Beat in flour just until blended, then stir in sprinkles. Spread into prepared pan.
Bake until browned at edges and firm, 25 min. Cool completely.
Make the frosting: Beat together butter, shortening, confectioners' sugar, milk, vanilla and salt. Spread over cooled bars. Top with sprinkles and cut into bars. Makes 24 bars.