Macaroni and cheese

This recipe came from a box of Barilla elbow macaroni. It's gotten rave reviews whenever I've made it. I wanted to e-mail it to a friend of mine recently but left the recipe at home, so I did some extensive searching online. Out of the dozens of recipes I found, there wasn't anything similar to this one, even on the Barilla Pasta site! Anyway, I remembered to bring the recipe with me to work and I'm posting it here for posterity. It's really good.

"Extraordinary" Macaroni and Cheese

1/4 cup (4 tbl.) butter
1 cup chopped onion (optional, but I highly recommend it)
1/8 cup all-pupose flour
1 tsp. salt
3 cups milk
1/2 lb. (8 oz.) elbow macaroni, uncooked
1 and 1/2 cups cheddar cheese, shredded

Melt butter in a 4-quart saucepan over medium heat. Add onions and saute until transparent. Stir in flour and salt. Cook 1 minute, stirring constantly.

Add milk, stir to blend. Bring to a low, steady simmer. Add uncooked macaroni. Cover, and continue to simmer gently for 8 minutes, stirring occasionally. (Mixture will thicken as it cooks.)

Remove from heat. Add cheese. Stir gently until cheese is melted. Let sit 5 minutes before serving.

OPTIONS: Top with additional 1/2 cup cheese and broil until cheese is melted. For an Italian twist, substitute cheddar cheese wth 1 cup fontina cheese and 1/2 cup freshly grated Parmesan cheese.