Vanilla Unicorn Sugar Cookie Bars

Name: Vanilla Unicorn Sugar Cookie Bars
Cuisine: American
Ingredients: For the Sugar Cookie Base; 2 1/4 cups all-purpose flour; 1/2 teaspoon baking powder; 1/4 teaspoon baking soda; 1/2 teaspoon salt; 1/2 cup unsalted butter, softened; 1 cup granulated sugar; 1 large egg; 2 teaspoons vanilla extract; 1/2 cup sour cream; For the Vanilla Frosting; 1/2 cup unsalted butter, softened; 2 cups powdered sugar; 2 tablespoons heavy cream; 1 teaspoon vanilla extract; Pink food coloring; For Topping; Assorted colorful sprinkles