8 oz spaghetti or other long pasta, 1 lb boneless, skinless chicken breasts, 2 tbsp butter, 1 onion- finely chopped, 2 cloves of garlic -minced, 2 cups chicken broth, 1 cup heavy cream, 1 cup grated Parmesan cheese, 1/2 cup all-purpose flour, Salt and pepper, to taste, 1/4 tsp dried thyme, 1/4 tsp nutmeg, 1 cup frozen peas, 1 cup sliced mushrooms