Preheat oven to 350 degrees.
Mix butter, Crisco, sugar, egg yolk and vanilla. Blend flour and salt, and stir into the butter mixture. Roll dough into balls using about 1 teaspoon of dough. Beat egg white. Dip balls into egg white and then roll in nuts. Place about 1 inch apart on an ungreased cookie sheet.
Bake for about 10 to 12 minutes. About halfway through the baking time, take the cookies from the oven and using a thimble (or the end of a spoon handle) gently make an indent in the center that will hold a helping of jelly once the cookies are cool.
Makes about 2 1/2 dozen.
Source: Claudia LaBorde, Tampa; Marion Haupt, Zephyrhills; Carmen Hunter, Tarpon Springs; Beverly J. Bartosch, Spring Hill.