PREHEAT oven to 350° F. Grease 13 x 9-inch baking pan.
BEAT brown sugar and butter in a large mixer bowl until creamy. Beat in oats, flour, dry milk, 1/2 cup toffee bar pieces and salt. Press evenly onto bottom of prepared baking pan.
BAKE for 18 to 20 minutes or until edges are lightly browned and center is still slightly soft. Remove from oven to wire rack. Sprinkle with morsels. Let stand for 3 minutes or until morsels are shiny; spread evenly. Sprinkle with remaining toffee bar pieces. Cool for 1 hour. Cut into bars as needed. Cover; store at room temperature. In warm climates, bars may be stored refrigerated. Bring to room temperature before cutting.