Tired of tomato sauce with your pasta? This white sauce is a nice change of pace. Mushrooms and Italian sausage compliment each other well. Don't skip the steps in sauteeing the mushrooms -- this gives the dish its great flavor. A great recipe for entertaining! I made the stuffed pasta ahead of time, covered it and kept it in the refrigerator for several hours. Then quickly made the sauce just before baking. A hit at our dinner party!