Mix butter mixture into flour mixture, until a crumbly dough is formed. Add sprinkles and mix.
Dump cookie dough out onto parchment paper or foil, and form into a firmly packed rectangle shape that is 1 inch in height.
Chill dough in refrigerator for at least 30 minutes.
Preheat oven to 350°F.
After dough has chilled, cut dough into 1 inch slices, and then into 1 inch cubes. Place cubes onto a silicone mat lined baking pan or a baking pan sprayed with cooking spray.
Bake for 20 minutes or until slightly golden brown on the bottom edges.