Thimble Cookies

1 1/2 sticks butter

1/2 cup sugar

4 egg yolks

1 tsp. vanilla

2 cups flour

1/4 cup Cider Jelly

Cream butter and sugar. Beat in yolks and vanilla. Gradually work in flour. Shape into 1" balls. Place on ungreased baking sheet. With a floured thimble or thumb, press a hole into each ball and fill with jelly. Bake at 325 for 25 min.