Terrific Toffee Bars

1 cup butter, softened

1 cup packed brown sugar

1 teaspoon vanilla extract

1 large egg yolk

2 cups all-purpose flour

¼ teaspoon salt

⅔ cup milk chocolate chips

½ cup chopped walnuts

Preheat oven to 350 degrees F (175 degrees C). Lightly grease a 9x13-inch baking dish.

Beat butter, brown sugar, vanilla extract, and egg yolk in a large bowl; stir in flour and salt. Press dough into prepared baking dish.

Bake in preheated oven until crust is light brown, 25 to 30 minutes.

Immediately sprinkle chocolate chips over hot crust. Let stand until soft, about 5 minutes, and spread evenly; sprinkle with nuts. Cool pan on wire rack for 30 minutes.