1 c Butter 1/2 c Brown sugar 1/2 c Sugar 1 ea Egg yolk 1 ts Vanilla 2 c Flour 10 oz Chocolate chips 1 c Finely chopped nuts Cream butter and sugar, add egg yolk and vanilla. Stir in flour. Spread mixture thinly on greased cookie sheet. Bake at 350 degrees for 15 to 20 minutes. Melt chocolate over hot water and spread over warm baked cookies. Sprinkle on nuts and press them firmly. Cut in bars while still warm. Let stand until chocolate is dry.