1 cup unsalted butter, softened
1/2 cup sugar
2 egg yolks
1 teaspoon vanilla extract
2 cups all purpose flour
1/2 teaspoon salt
jelly or jam of your choice
In large bowl of mixer with mixer at medium speed, cream butter and sugar until light and fluffy. Beat in egg yolks and vanilla. Gradually add flour and salt until well blended. Refrigerate dough 1 hour.
Preheat oven to 350. Work with only 1/4 of dough at a time; keep remaining refrigerated. Roll dough into 1-inch balls. Place on ungreased cookie sheet about 2 inches apart. Using your thumb or the end or a wooden spoon make a depression in the center of each. Bake for 10 minutes. Remove cookies from oven. make the depression again. Fill each depression with 1/4 teaspoon jelly or jam and return to oven to bake 5 more minutes. Cool on wire rack. Makes about 4 dozen.