3 or 4 c. chopped, cooked chicken
1 onion, chopped
12-16 oz. chopped fresh mushrooms
3/4 lb. thin spaghetti
1 c. butter, divided into half c.
1/2 c. plain flour
3 c. half & half
1 1/2 c. milk
1/2 c. chicken stock
1 c. sharp Cheddar cheese, grated
1/2 c. grated Parmesan cheese
Juice of 1 lemon
1 tbsp. prepared mustard
1 tbsp. parsley, minced
Salt and pepper to taste
1 c. mayonnaise

Cook chicken (reserve 1/2 cup chicken stock). Chop chicken and set aside. Saute onions and mushrooms in 1/2 cup butter. Set aside. Cook noodles according to directions on box, set aside.

SAUCE:

Melt 1/2 cup butter and blend in flour. Slowly add cream, milk and broth. Cook until thickened, stirring constantly (this will take a while, be patient).

When thickened, add cheeses and lemon juice. Season with parsley, mustard, salt and pepper. Remove from heat and add mayonnaise. When mixed, add chicken, mushrooms and onions (saute) and cooked noodles. Bake uncovered at 350 degrees for 30 minutes. Serves 10-12. Can do ahead.