03Bring broth to a boil. Break spaghetti into thirds (shorter pieces). Add spaghetti pieces to boiling broth and cook. Drain when al dente. Remove meat from bones and shred until you have 2-plus cups of shredded chicken.
04Return large skillet to medium-low heat. Add 6 tablespoons butter. Sprinkle flour over butter, whisking to combine. Cook for 1 or 2 minutes. Pour in 2 cups broth and whisk to combine. Pour in milk, additional 1/4 cup wine, salt and pepper to taste, then cook and bubble until thick. Turn off heat, add Parmesan cheese, and stir.
05Add mushrooms, chicken, and chopped olives. Stir to combine and check seasonings. Add cooked spaghetti and stir.
06Turn into a 9 x 13 casserole pan. Bake at 350 degrees or until golden brown and bubbly. Serve with salad and warm, crusty bread.