Chicken With Grape Mustard Cream

1 c Sliced fresh mushrooms

2 tb Butter

2 tb Minced onion

4 Boneless, skinless chicken

-breast halves (~1 lb) 1/2 c Dry white wine

1 t Dried marjoram

1/4 ts Salt

1/4 ts Pepper

1/4 c Heavy cream

1 tb Dijon-style mustard

1 tb Flour

1 1/2 c Seedless green California

-grapes

Place mushrooms, butter and onion in an 8" square glass dish. Cover with plastic wrap. Stirring midway through cooking, microwave on high 2 minutes. Arrange chicken on top of mushroom mixture. Add wine, marjoram, salt and pepper. Re-cover and microwave on high 5-6 minutes, or until chicken is no longer pink. Combine cream, mustard and flour in a 2-cup glass measure. Drain liquid from chicken into it; re-cover chicken and set aside. Stirring after each minute, microwave on high 3-4 minutes, or until mixture thickens and bubbles. Stir grapes into sauce and microwave on high 1-2 minutes, or until grapes are heated through. Slice chicken crosswise and serve on warm plates topped with sauce.