In a large pot with boiling salted water cook the elbow macaroni until al dente. Drain and set aside.
In a 2-quart microwave-safe covered casserole dish, cook the onions and butter or margarine on high for 3 to 4 minutes.
Add the cooked and drained pasta, milk, and cubed cheese and stir. Cook for 11 to 12 minutes on high, stirring well after 4, 8, and 11 minutes. The mixture will still be runny at this stage. Add salt and pepper to taste.
Let stand for 5-8 minutes before serving. The sauce will thicken as it cools slightly.
recipepes.comMicrowave Macaroni and Cheese, recipePT15MPT1H5455 calories