Macaroni and Cheese

3 1/2 cups elbow macaroni, uncooked
1/4 cup butter
1/4 cup flour
1 tsp. salt
3/4 tsp. dry mustard
1/2 tsp. pepper
3 1/2 cups milk
5 cups cheddar cheese, shredded

Cook macaroni in boiling salted water until almost tender. In a small saucepan, melt butter. Stir in flour, salt, mustard and pepper. Cook and stir until smooth. Drain macaroni; combine with butter mixture in a large bowl and mix well. Stir in milk and 4 cups of cheese. Pour into an ungreased 13x9x2" baking dish. Cover and bake at 350 degrees for 45 minutes or until bubbly. Sprinkle with remaining cheese; Let stand 5 minutes before serving. Enjoy!