1 c. (2 sticks) butter
1/2 c. granulated sugar
4 egg yolks
1 tsp. vanilla extract
2 c. all-purpose flour
Any flavor jam or jelly

Preheat oven to 325 degrees. Cream butter and sugar. Add egg yolks and vanilla and beat until light and fluffy. Stir in flour and if necessary chill until firm enough to handle with floured hands. Roll into 1-inch balls. Put 1 1/2 inch apart on cookie sheets. Using a lightly floured thimble, make a small indentation in center of each cookie. Fill with jam. Bake about 25 minutes. Cool on racks. Makes about 4 dozen.