1Heat oven to 350°F. Cook spaghetti as directed on package, adding edamame and asparagus during last 3 minutes of cooking time; drain.
2Meanwhile, in 2-quart saucepan, melt butter over medium heat. Cook mushrooms in butter just until tender; remove from saucepan with slotted spoon and set aside. Stir flour, salt and pepper into same saucepan. Gradually stir in broth until mixture is smooth; stir in half-and-half. Heat to boiling, stirring constantly. Boil and stir 1 minute.
3Add mushrooms, spaghetti and vegetables, sherry, chicken and bell pepper to sauce; stir until combined. Spoon into ungreased 2-quart casserole.
4Bake uncovered 20 minutes. Sprinkle with cheese. Bake about 10 minutes longer or until bubbly in center.