Cream together margarine adding sugar slowly. Mix in egg yolk and vanilla extract. After sifting dry ingredients together slowly add creamed mixture. Roll into small balls and place on ungreased cookie sheet. Bake at 350 degrees for 5 minutes. After removing from oven, gently press maraschino cherry half or 1 gumdrop in the center of each cookie. Return to oven and continue baking for an additional 8-10 minutes. 2 cookies = 1 fruit exchange and 2 fat exchanges. Yields 2 dozen cookies.