1 1/2 c. butter, softened
1 c. sugar
3 egg yolks
3 c. sifted flour (more, if needed)
1 1/2 tsp. vanilla
Jelly or jam

Cream butter. Beat in sugar. Add egg yolks, flour and vanilla. Mix well. Roll dough into little balls. Place on ungreased cookie sheet. Make a thumb print in the center of each. Fill with jelly or jam. Bake a few at first. If they spread too much, add a little more flour to dough. Bake at 400 degrees until light brown around edges. 8 to 10 dozen.