Creamy Turkey Tetrazzini Casserole

Ingredients

• 1 package (7 ounces) spaghetti, noodles broken in half
• 2-3 cups cubed/shredded cooked turkey
• 1 1/2 cups shredded cheddar cheese
• 2 cans condensed cream of chicken soup, undiluted
• 1 large onion, chopped
• 2 Tbs butter
• 1 can sliced water-chestnuts
• 3/4 cup sour cream
• 1/4 cup milk
• 1 jar (2 ounces) chopped pimentos, drained
• 1/4 teaspoon salt
• 1/8 teaspoon pepper
• 2-3 Roma tomatoes, sliced
• Fresh or dried parsley
• Sliced mushrooms, optional
• Diced roasted red, orange or yellow peppers, optional