Hershey Bar Cookies

1 cup butter
1 cup margarine
Blend together with 1 egg yolk.
Add :
1 cup brown sugar
1 cup flour

Topping:
5 Hershey candy bars
Chopped nuts

Mix well.
Spread in a 9 x 13 pan. Bake 20 - 25 minutes at 350 degrees. While hot, break Hershey bars over the top, melt, and spread. Top with chopped nuts.

This is from Wally's mom, Alice. His sister, Jinny, loves to make it for our Christmas desserts.