These yummy dessert bars are topped with melted chocolate and chopped nuts.
Heat oven to 350°F. Grease 9 x 13-inch baking pan. In large bowl, with mixer on high, beat butter and sugar until light and fluffy, about 3 minutes. Add yolk and vanilla, and beat until combined. Reduce mixer speed to low, and add flour and salt until soft dough forms.
Press dough evenly into bottom of pan. Bake 25 minutes or until browned. Sprinkle chocolate pieces on top, and bake 5 minutes longer. Remove from oven; with knife, spread melted chocolate to cover. Top with nuts, gently pressing into chocolate. Let cool completely. Cut into 48 bars.