Ingredients
For the Cookies
1 1/2 cups butter, softened
2 cups white sugar
4 eggs
1 teaspoon vanilla extract
5 cups all-purpose flour
2 teaspoons baking powder
1 teaspoon salt
For the icing
1/2 cup milk
3 cups confectioners (powdered or icing) sugar, sifted
red and blue food coloring
Directions
For the cookies: in a large bowl, cream together butter and sugar until smooth. Beat in eggs and vanilla. Stir in the flour, baking powder, and salt. Cover, and chill dough for at least one hour (or overnight). Preheat oven to 400F. Roll ut dough on floured surface 1/4 to 1/2 inch thick. Using a 2 inch round or scalloped cookie cutter, cut out cookies. Place cookies 1 inch apart on ungreased cookie sheets. Bake 6 to 8 minutes in preheated oven. Cool completely.
To make the icing: whisk together milk and powdered sugar until smooth. It should be a fairly loose icing. Split the batch in half, reserving one half and cover half with plastic wrap. Split remaining half in half again, adding blue color to one and red to the other. Fill red and blue icing into piping bags fitting with #1 tips.
To decorate: using a food-safe paintbrush, paint each cookie completely white. While still wet, draw circles of colors on each tile (3 or 4 rings). While still wet, drag a toothpick from the center to the edges, creating fireworks effect. Note: you must do this fairly quickly, so you might want to work in batches.