Heat oven to 350°F. Spray 13x9-inch (3-quart) baking dish or 3-quart baking dish with cooking spray. Cook and drain spaghetti as directed on package using minimum cook time. In 4-quart Dutch oven or saucepan, melt 3 tablespoons of the butter over medium heat. Cook and stir onion in butter 3 minutes or until onion begins to soften. Stir in bell pepper and mushrooms. Cook and stir 5 to 8 minutes longer or until vegetables are tender.
Stir sherry, Alfredo sauce and 1/2 cup of the cheese into mushroom mixture. Cook and stir about 2 minutes or just until hot and ingredients are blended. Stir in turkey and spaghetti. Spoon into baking dish.
In small bowl, stir together bread crumbs, remaining 2 tablespoons butter and remaining 2 tablespoons cheese. Sprinkle crumbs and almonds evenly over mushroom mixture. Bake 30 to 35 minutes or until hot and topping is golden brown.