1 cup (2 sticks) butter or margarine, softened
1 cup firmly packed brown sugar
1 egg yolk
1 teaspoon vanilla extract
2 cups all-purpose flour
1/4 teaspoon salt
1 3/4 cups (10 ounces) semisweet chocolate chunks
1 cup coarsely chopped pecans

Preheat oven to 350 degrees F. Grease a 9 x 13-inch baking pan.

In large mixer bowl, stir together butter, brown sugar, egg yolk and vanilla extract. Blend in flour and salt. Press mixture onto bottom of prepared pan. Bake 25 to 30 minutes, or until lightly browned. Remove from oven and sprinkle chocolate chunks on crust. Let stand until softened, about 5 minutes. Spread evenly over crust and sprinkle with pecans. Cool completely.