PREHEAT oven to 375°F Grease 9-inch-square baking pan.
COMBINE flour, baking soda and salt in small bowl. Beat sugar, butter and vanilla extract in large mixer bowl until creamy. Beat in egg; gradually beat in flour mixture. Stir in morsels and chopped toffee. Spread into prepared baking pan.
BAKE for 20 to 23 minutes. Remove pan to wire rack. Cool completely in pan on wire rack; refrigerate for 5 to 10 minutes or until chocolate is set. Cut into bars.