In a mixing bowl combine dry cake mix and walnuts. Stir in evaporated milk and the melted butter or margarine. Spread about half of the cake mixture in a greased 13 x 9 x 2 inch baking pan. Bake in a 350 degree oven for 10 minutes. Remove from oven. If desired, sprinkle chocolate pieces over hot crust. Drizzle with caramel topping. Drop remaining cake mixture by teaspoons over all. Bake in 350 degree oven for 20 to 25 minutes more. Cool on wire rack. While still warm, loosen sides and cut into bars.
