Truffles

Melt together over low heat 4 squares unsweetened chocolate and 1/3 c. butter (not margarine). Let cool. Stir in 2 cups sifted powdered sugar. Add four egg yolks one egg yolk at a time. Add one tsp. of real vanilla. Chill two hours. Form into perfect balls. Roll in powdered sugar, ground nuts or cocoa. Store covered in the refrigerator.