Toffee Bars

1 cup brown sugar

1 cup butter

1 egg yolk

1 tsp vanilla

2 cups flour

Preheat oven to 350 degrees.  Cream butter and sugar well and add egg yolk and vanilla.  Mix. Add flour and mix well.  Pour in a greased 15*10 jellyroll pan.  Bake 15 to 18 minutes.  Remove from oven.  Cover with 1 cup melted chocolate bits.  Cut into squares.