Toffee Squares

1 cup butter
1 cup brown sugar
2 cups flour
2 tablespoons margarine
1 egg yolk
1 teaspoon vanilla extract
1 (8 ounce) plain Hershey bar
1 cup nuts, chopped

Heat oven to 350 degrees F.

Cream butter and sugar until light. Add beaten egg yolk, vanilla extract and sifted flour. Spread thinly on a cookie sheet or jellyroll pan and bake for 15 to 20 minutes. Cool slightly.

Melt chocolate with margarine in a double boiler and spread on cookie surface. Sprinkle with nuts and cut into squares.