1 c. butter
1 c. firmly packed light brown sugar
1 egg yolk
1 tsp. vanilla
2 c. unbleached flour
1 c. semi-sweet chocolate chips
1/2 cup small walnut pieces
Preheat oven to 350. Grease jelly roll pan (10x15x1).
In large mixer bowl, cream butter; add sugar gradually & beat until light. Blend in egg yolk & vanilla. Add flour & bend until combined.
Spread dough evenly into pan.
Bake for 18-20 minutes until edges just begin to brown. Do not overbake. Remove from oven to wire rack & sprinkle immediately with chocolate chips, allow to melt & spread evenly over cookie base. Sprinkle with nuts; press into lightly chocolate.
Cut into squares. Store tightly covered in refrigerator.