1 cup butter, softened
1-1/2 cups sugar
1 large egg
3-1/3 cups flour
1/2 teaspoon baking soda
1/2 teaspoon salt
1 teaspoon cream of tartar
2 teaspoons vanilla
Colored sugar crystals, icing or candies for decorating
Beat butter until creamy, about 2 minutes. Add sugar gradually, beating well. Add egg and beat in. Combine flour, soda, salt, and cream of tartar; add to butter mixture, beating at low speed just until blended. Stir in vanilla.
Shape dough into a ball. Roll dough to a 1/4-inch thickness on wax paper. Cut into desired shapes and place 2 inches apart on ungreased cookie sheets. Sprinkle dough with sugar crystals before baking, if desired. Bake at 350 degrees for 12 minutes or until edges are lightly browned. Cool and decorate as desired.