3/4 c. packed brown sugar
1/3 c. butter, softened
3/4 tsp. vanilla
1 egg yolk
1 (6 oz.) pkg. semi-sweet chocolate chips
1/2 c. chopped nuts
2 c. Bisquick

Heat oven to 350 degrees. Mix brown sugar, butter, vanilla and egg yolk. Stir in baking mix; mixture will be crumbly. Press evenly into 9x13x2 inch pan. Bake until light brown, 16 to 18 minutes.

Immediately sprinkle chocolate chips over top. Let stand until chips are soft, 3 to 4 minutes. Spread evenly. Sprinkle with nuts. Cut into squares.