Old Fashion Macaroni and Cheese

Why I Love This Recipe
I'm not sure where I got this recipe but I can tell you it's a hit. I took it yesterday for the school administrator's cookout and brought home only an empty dish. That may not sound like a lot until you consider I had to compete against five other Mac and Cheese dishes.
Ingredients You'll Need
1 8 oz package elbow macaroni
1/4 cup butter
3 tablespoons all purpose flour
1/8 teaspoon dry mustard
1/8 teaspoon salt
1/8 teaspoon black pepper
2 cups milk
2 cups (8 oz) shredded sharp cheddar cheese
1 cup croutons (sometimes I just sprinkle the top with bread crumbs)
Directions
Heat oven to 350.
Cook macaroni as package directs, decreasing time to 3 minutes; drain.
In medium saucepan, 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 cheese. Cook and stir over low heat until melted.
Add pasta and mix lightly. Pour into 2 quart casserole and top with croutons.
Bake 25 minutes.