PREPARATION:

1. Preheat oven to 350°F. Cook noodles according to package directions. Drain; set aside.
2. Melt butter in large nonstick skillet over medium-high heat. Add mushrooms and onions; cook and stir until onions are tender. Add chicken broth, 1/2 cup half-and-half and sherry to onion mixture. Pour remaining 1/2 cup half-and-half into small jar with tight-fitting lid; add flour, salt, nutmeg and pepper. Shake well. Slowly stir flour mixture into skillet. Bring to a boil; cook 1 minute. Reduce heat; stir in pimiento and 1/4 cup Parmesan cheese. Stir in sour cream; blend well. Add chicken and noodles; mix well.
3. Spray 1-1/2-quart casserole with nonstick cooking spray. Spread mixture evenly into prepared casserole. Sprinkle with remaining 1/4 cup Parmesan cheese. Bake 30 to 35 minutes or until hot.