Mix butter with sugar until very light and fluffy. Add cornstarch and flour, mixing well. Refrigerate until easy to handle. Preheat oven to 350 degrees. Shape dough into 1-inch balls. Place balls on pecans, scattered on waxed paper. Flatten out with bottom of a glass dipped in flour. With spatula place cookies on ungreased cookie sheet, nut side up. Bake 15 minutes. Cool. Frost with Bon Bon Frosting.

Directions for Bon Bon Frosting.

Blend sugar, butter, and lemon juice until smooth. Divide into thirds. Tint each part a different color with food coloring. Swirl frosting on top of each cookie.