¾ cup butter, softened
½ cup white sugar
1 tsp vanilla extract
2 egg yolks
¼ tsp salt
1 ¾ cups AP flour
½ cup jam or preserves, any flavor
Preheat the oven to 375 degrees. Cream together the butter, sugar, vanilla and egg yolks. Mix in salt and add flour a little bit at a time until a soft dough forms. Roll dough into 1 inch balls. If dough is too soft to work with, refrigerate for 15-20 minutes. Place balls 2 inches apart on cool ungreased baking sheets.
Use your thumb or the handle of a wooden spoon to make an indentation in the center of each cookie. Spoon your jam into a sandwich bag and snip off a tiny corner of the bag. Use this to pipe about ½ tsp. of jam into each indentation. Bake at 375 for 8-10 minutes or until golden brown on the bottom. Cool on wire racks.