OLD FASHIONED BAKED MACARONI AND CHEESE

1/4 pkg (8 oz) elbow macaroni
1/4 cup butter/margarine
3 tsp flour
1/8 tsp dry mustard
1/8 tsp salt (optional)
1/8 tsp black pepper
2 cups milk
2 cups (8 oz) shredded sharp cheddar
1 cup croutons
2 cups (8 oz) shredded parmesan

Heat oven to 350. Cook macaroni as package directs, decreasing time to 3 minutes; drain. In medium sauce pan, melt margarine. Blend in flour, mustard, salt and pepper. Cook until mixture is smooth and bubbly; gradually add milk. Cook and stir over medium heat until mixture boils. Simmer 1 minute, stirring constantly. Gradually stir in cheeses. Cook and stir over low heat until cheese is melted. Add pasta, mix lightly. Pour into 2 qt casserole. Top with croutons.
Bake 25 minutes.