Ultimate Bar Cookies

In a medium mixing bowl beat flour, brown sugar, and butter with an electric mixer on medium speed until mixture forms fine crumbs. Pat firmly into an ungreased 13x9x2-inch baking pan. Bake in a 350F degree oven for 15 minutes or until lightly browned. Transfer the pan to a wire rack.

Sprinkle nuts, white and milk chocolate over the hot crust. Heat and stir the 3/4 cup butter and remaining brown sugar over medium heat until bubbly. Cook and stir for 1 minute. Pour evenly over layers in pan. Bake 15 minutes more or until just bubbly around edges. Cool in pan on rack. Cut into bars.