THIN WHITE SAUCE:

2 c. milk
2 tbsp. butter
1 tsp. salt
1/2 tsp. pepper
2 tbsp. flour

MACARONI & CHEESE:

1 (8 oz.) box elbow macaroni
3 c. shredded cheddar
1 tsp. salt
1/2 tsp. pepper
2 tbsp. grated onion

Heat oven to 375 degrees. Prepare white sauce; melt butter in pan, add flour, salt and pepper. Cook and stir until smooth and bubbly, low heat. Add milk. Bring to boil, stirring continuously; boil for 1 minute; remove from heat. Cook macaroni. Place 1/2 of macaroni in 2 quart casserole. Sprinkle 1/2 of onion, cheese, salt and pepper over macaroni. Add remaining macaroni, sprinkle with remaining cheese, onion, salt and pepper. Pour sauce over top. Cover and bake 30 minutes. Uncover and bake 15 minutes more.