01 -
Preheat oven to 375°F and grease a 9x13 inch baking dish.
02 -
In a large bowl, cream together the softened butter and sugar with an electric mixer until light and fluffy, about 3 minutes.
03 -
Beat in the egg, then add vanilla extract and sour cream until fully combined.
04 -
In a medium bowl, whisk together flour, salt, and baking powder. Gradually add the dry mixture to the wet mixture, mixing 1/2 cup at a time until incorporated.
05 -
Divide the dough into two equal portions. Tint one with black food coloring and the other with orange food coloring.
06 -
Press the black dough evenly into the baking dish. Flatten the orange dough slightly in your hands, then layer it over the black dough, pressing evenly to edges.
07 -
Bake for 22–24 minutes until edges are lightly golden. Remove and allow to cool completely.
08 -
In a medium bowl, cream butter until smooth. Alternate adding confectioner's sugar and half & half until fluffy. Mix in vanilla extract and tint with purple food coloring.
09 -
Spread frosting evenly over cooled cookie bars. Add sprinkles while frosting is still soft.