Cook spaghetti al dente according to package directions.
Cook butter, onions and garlic over medium heat until softened. Add mushrooms and cook an additional 3 minutes. Stir in flour and cook 1 minute.
Add broth and cream all at once. Cook until thick & bubbly, let boil 1 minute. Stir in cream cheese until melted. Add parsley and seasonings
Combine spaghetti, turkey, 1 cup of mozzarella cheese and sauce. Pour into a greased 9×13 pan. Top with remaining mozzarella, cover and bake 20 minutes. Sprinkle with Parmesan and bake an additional 10-15 minutes uncovered until hot & bubbly.