In large bowl with mixer, beat at medium speed butter and sugar until smooth. Beat in syrup and egg yolks. Stir in flour. Chill 1 hour. Shape into 1-inch balls. Dip into slightly beaten egg whites. Roll into nuts. Place 2 inches apart on greased cookie sheet.

With thumb, make indentation in center of each. Bake in 325 degree oven for 20 minutes until golden. If necessary, press again with thumb. Remove from cookie sheet. Place on rack. While still warm, fill with jam or cherries.