1/2 c. butter
1/2 c. shortening
1 c. brown sugar
1 egg yolk, beaten
1 tsp. vanilla
2 c. flour
1/2 tsp. salt

Cream butter, shortening and sugar together. Add egg yolk, vanilla, flour and salt. Beat till smooth. Pat on ungreased cookie sheet. Bake 12 minutes at 350 degrees. Let cool. Spread melted chocolate (chocolate chips or Hershey bars) over top and cut in squares.