Chocolate Chip Thumbprint Cookies

1 c. semi-sweet chocolate chips
1/4 c. margarine, softened
1/4 c. shortening
1/2 c. sugar
1 egg, separated
1/2 tsp. vanilla extract
1 c. flour
1/4 tsp. salt
1 c. chopped nuts

In small microwave-safe bowl, place 1/4 cup chocolate chips. Microwave at high for 20 to 30 seconds or just until chocolate is melted and smooth when stirred. Set aside to cool slightly. In large mixer bowl, combine butter, shortening, sugar, melted chocolate, egg yolk and vanilla. Blend well. Stir in flour and salt. Roll dough into one inch balls. With fork, slightly beat egg white. Dip each ball into egg white. Roll in chopped nuts. Place balls on ungreased cookie sheet, about one inch apart. Press center of each ball with thumb to make indentation. Bake at 350 degrees place several of remaining chocolate chips in center of each cookie. Carefully remove from cookie sheet to wire rack. After several minutes, swirl melted chocolate in each thumbprint. Makes about 2 1/2 dozen cookies.