Preheat oven to 350 degrees.
In a large skillet melt bacon grease over medium heat. Sauté onions, peppers, celery and garlic for 4-5 minutes. Add pimentos, salt, granulated garlic and cooked chicken. Cook three to four more minutes. Remove mixture from heat and transfer to a large mixing bowl. Add the mushroom béchamel sauce, sour cream, Worcestershire and cheeses. Mix well. Bring chicken broth to a boil in a large stockpot. Cook the spaghetti in broth for approximately 12 minutes. Drain spaghetti and transfer to the chicken mixture. Mix well and place into a buttered three-quart baking dish. Cover tightly with foil. Bake 40 minutes. Serve immediately.
Yield: 8-10 servings