Make a white sauce with 2 tablespoons butter and enough flour to make a thick paste. Add salt to taste and 2 cups of milk. Stir constantly until thickened. When thickened add chunks of cheese, Velveeta or white cheddar. Mix until melted. Add to 1 1/2 cups cooked macaroni. Sprinkle the top with bread crumbs. Bake in a casserole dish for 1/2 to 3/4 hour at 325 degrees.