1 c. evaporated milk
1 c. sugar
3 egg yolks
1/2 c. butter
1 tsp. vanilla
1 1/2 c. cocoa
1 c. walnuts

Combine first 5 ingredients. Cook until thick, about 10-13 minutes. Add coconut and walnuts, chopped. Beat. Spread on cake. This is especially good on German Chocolate Cake.