1 1/2 lb. bag spaghetti or fettuccini, cooked (I've also used macaroni, penne, spirals, etc.)
2 Cans Cream-of-whatever soup (or 2 Tbsp. melted butter mixed with 2 Tbsp. flour, 2 Cups milk, stirred and cooked until slightly thickened, salt and pepper to taste)
2 Cups cooked, diced chicken, turkey, ham, shrimp, etc.
1 soup can milk (or make up some powdered milk for better value)
Salt and pepper to taste
1 Cup frozen peas (or clean out the fridge for leftover veggies!)
1 Cup sliced mushrooms, optional
2-3 Cups grated cheddar, monterey jack, or whatever you have on hand
Mix everything together in one large greased casserole for a larger family, 2 smaller ones for a smaller family and freeze one for later. Grate a little cheese over the top, and throw in the oven at 350F for about 35-40 minutes.