1 c. butter
1 c. brown sugar
1 egg yolk
2 c. flour
1 tsp. vanilla
10 Hershey bars
Walnuts

Cream butter and sugar, add egg yolk, flour and vanilla. Mix well. Spread on large buttered pan (jelly roll size). Pat even. Bake 20 minutes at 350 degrees. Remove from oven, place bars on top. Return to oven for about 1 minute. Remove and spread chocolate with knife. Cut in squares. If desired, sprinkle chopped walnuts on top.