Toffee Bars - cooking recipe

Ingredients

1 c. butter (2 sticks)
1 c. light brown sugar
1 egg yolk
2 c. all-purpose flour
1 tsp. vanilla extract
12 oz. semi-sweet chocolate chips
1 c. shelled walnuts or pecans, chopped

Preparation

Preheat oven to 350\u00b0.
Grease a 9 x 12-inch baking pan.
Cream butter and sugar. Add egg yolk and beat well.