Preheat oven to 325 degrees.

In a medium bowl, cream butter with electric mixer at medium
speed. Add sugar and beat until smooth. Add egg yolks and
vanilla, and beat at medium speed until light and fluffy. Add the
flour and blend at low speed until thoroughly combined.

Gather dough into a ball and flatten to a disk. Wrap dough tightly in
plastic wrap or place in a plastic bag. Refrigerate 1 hour.

Using a floured rolling pin, roll dough on floured board to 1/4 inch
thickness. cut circles with a 2 inch diameter cookie cutter or
drinking glass, and place on ungreased cookie sheets, 1 inch
apart. Continue using the dough scraps, rerolling and cutting until
all the dough is used.

Drop 1/2 teaspoon of fresh jam in the center of each cookie, then
top with another cookie. Using the tines of a fork, seal edges of
cookies.

Bake for 15 to 17 minutes or until edges begin to brown.

Recipe credit:  Unknown