Thumbprint Cookies

Preheat oven to 350 degrees F. Lightly grease cookie sheets, or line with parchment paper or foil and set aside. In a large bowl, combine butter and sugar and beat until light and fluffy. Beat in egg yolks, vanilla, and salt, then stir in flour. Shape dough into 3/4 inch balls. Dip in lightly beaten egg whites, then roll in finely chopped pecans or coconut. Place 1 inch apart on prepared cookie sheets. Using your thumb, press down in the center of the cookies to make an indentation. Bake at 350 degrees F for 12 to 15 minutes, or until light golden brown. Cool on cookie sheet for 3-5 minutes, then remove to wire racks to cool completely. Tint Buttercream Frosting with food coloring and fill imprint in completely cooled cookies. Top with candies to resemble eggs in bird's nests. Makes about 24 cookies.