Cook spaghetti pieces till just tender; drain. Heat butter in 3 qt. saucepan until melted. Stir in flour, salt, and pepper. Cook, stirring constantly , until smooth and bubbly; remove from heat. Stir in broth and half-and-half. Heat to boiling; stirring constantly. Boil and stir for 1 minute. Stir in cooked spaghetti, chicken, and mushrooms. Pour into ungreased casserole dish. Sprinkle with cheese. Cook, uncovered, in 350 degree oven until top is golden brown, about 30 minutes. Posted to MM-Recipes Digest by IceTeaLuvr@aol.com on Aug 21, 1998,