2 egg yolks
2 tablespoons milk
2-1/4 cups all-purpose flour
3/4 cup sugar
3/4 cup butter, softened
1 teaspoon vanilla extract
1/4 teaspoon salt

Preheat oven to 375°F.

In large bowl, with mixer at low speed, beat egg yolks and milk until well blended. Add flour, sugar, butter, vanilla and salt; beat ingredients until just mixed. Increase speed to medium and beat 2 minutes, occasionally scraping bowl. Divide dough in half.

On floured pastry cloth, with lightly floured stockinette-covered rolling pin, roll one dough half 1/8-inch thick. With 2 1/4-inch fluted-edged cookie cutter, cut dough into rounds; with 1/2-inch round cutter, cut out centers

Using a pancake turner, place rounds 1/2-inch apart on ungreased cookie sheets.

Bake at 375°F for 8-10 minutes until lightly browned. With pancake turner, remove cookies to wire racks to cool completely.

Repeat cutting and baking with second half of dough, rerolling scraps.

BUTTER CREAM FROSTING:

4 tablespoons sweet butter
1/2 cup solid shortening
1 pinch salt
1/2 pound confectioners' sugar
1-1/2 tablespoons milk
1/2 teaspoon vanilla
1/2 tablespoon water
3 drops green food color
3 drops red food color
3 drops yellow food color

In the bowl of an electric mixer, place all frosting ingredients (except food color) and beat at low speed for 2 minutes. Scrape sides of bowl and continue beating at high speed for 6 minutes. Divide frosting into thirds and tint with food color.

On bottom side of cookie without a hole, spread teaspoonful of either green, pink or yellow frosting; top with a cookie with a hole in it to make a "sandwich." Repeat with remaining cookies and frosting. (Use any leftover frosting for graham crackers or cupcakes.)

Makes about 42 sandwich cookies.