1crust: cream 3/4 cup butter or margarine the flour and the brown sugar until well blended. Press evenly into prepared greased 13 x 9 inch pan bake in 350 degree oven for 20-25 min. Cool on rack while preparing filling.
2filling: Het sweetened condensed milk and butter in heavy saucepan. Stir constantly 5-10 min or until thickened. Spred over baked base. Bake for 12-15min or until golden. Sprinkle chocolate chips over top. Bake 2 min longer.
3spread chips then sprinkle toffee bits on top. Cool before cutting into bars.