Macaroni and Cheese Bake

1/4 cup margarine
1/4 cup flour
1/2 tsp. salt
2 cups milk
2 cups grated cheddar cheese
2 cups cooked elbow macaroni
1/4 cup bread crumbs
1/4 cup grated parmesan cheese

Boil macaroni, strain. Prepare cheese sauce. Top with bread crumbs and parmesan and a little more cheddar cheese. Bake in an uncovered casserole dish.
Makes four servings. Prep time 15 minutes. Bake at 350 F for 20-25 minutes.