Cream butter into a large bowl. Beat in sugar and vanilla until light and fluffy. Add flour and pecans mix well. Chill dough in tightly covered container 4 hours or overnight. Remove foil from 15 kisses. Shape dough around kiss using 1 teaspoon per kiss. Bake 12 minutes on ungreased cookie sheet until set, but NOT brown. While warm, sprinkle with powered sugar.
Store in covered container.