French Buttercream Cookies

1 1/2 cups confectioners' sugar
1 teaspoon cream of tartar
1 cup butter or margarine, room temperature
1 teaspoon vanilla extract
1 teaspoon baking soda
1/4 teaspoon salt
1 large egg
2 1/4 cups all-purpose flour

In a large bowl, combine sugar, cream of tartar, butter, vanilla extract, baking soda, salt and egg on low speed for 1 minute. Add flour gradually, blend at low speed. Chill dough for 15-30 minutes before shaping.

Shape into 3/4 inch balls, then place on greased cookie sheet about 2 inches apart. Flatten with fork. Sprinkle with sugar. Bake at 350 degrees F for 5-8 minutes. Let stand on cookie sheet about 1 minute.

Makes 4 dozen.