Cream butter and cream cheese together.
Add egg, vanilla; then mix in the flour.
Cover and chill for a few hours to overnight. Roll out on lightly floured board to ¼ inch thickness and cut with round cookie cutters. Place them on a cookie sheet as you would cookies. Use thumb to make indentation in center of each. Fill with about 1 teaspoon of desired filling. Bake at 350℉ (180℃) F until lightly golden, about 10 to 15 minutes.