1 cup butter, softened
1 cup firmly packed brown sugar
2 cups all-purpose flour
1 egg yolk
1 teaspoon pure vanilla extract
1 cup semisweet chocolate chips
1/2 cup chopped nuts
Preheat oven to 350°F.
Beat butter and brown sugar in a medium bowl until light and fluffy. Add flour, egg yolk and vanilla. Stir until thoroughly combined. Spread in an ungreased 9-inch square pan.
Bake for 15 minutes, or until edges are beginning to turn golden brown.. Remove from oven and immediately sprinkle with chocolate chips. Return to oven and bake for 5 more minutes, or until chocolate chips are softened. Gently spread chocolate over bars. Sprinkle with nuts. Cool completely before cutting.
Makes 9 bars.