Heat oven to 350 degrees F.Advertisement
Combine butter and sugar in the bowl of an electric mixer. Cream using the paddle attachment until light and fluffy. Add egg and vanilla, scraping the bowl as needed. Add the flour and mix just until incorporated (dough will be soft).
Roll 2 teaspoons of dough between your hands into a 1-inch ball. Repeat, spacing 2 inches apart on an ungreased baking sheet. With a floured thumb, make an indentation in the center of each. Fill each indentation with 1/2 teaspoon raspberry or apricot jam.
Bake at 350 degrees F about 10 to 12 minutes or until lightly golden brown around bottoms. Remove to a wire rack to cool.