1 (8 oz.) pkg. elbow macaroni
2 c. shredded American cheese
1 tbsp. flour
2 tbsp. finely chopped onion
1/4 tsp. dry mustard
1 1/2 tbsp. butter

Preheat the oven to 375°F. Cook macaroni in boiling water until tender. Drain and keep hot. In a mixing bowl, combine 1 cup of cheese with the flour, onion, mustard, salt and pepper. Add to the hot macaroni and mix well. Transfer to a buttered 2 1/2-quart casserole dish. Pour the milk over the macaroni. Top with remaining cheese and dot with butter.

Bake for 45 minutes or until the macaroni is firm and the top is golden brown.