Chicken San Souci

Ingredients

• 5 lb. chicken breast
• celery tops
• salt
• 2 boxes Uncle Ben's wild rice
• 1 large chopped onion
• butter
• 6 Tbsp. flour
• 3 cans cream of mushroom soup
• 2 1/2 soup cans milk
• 1 1/2 tsp. salt
• 1/2 tsp. black pepper
• 2 cans button mushrooms
• 1 lb. sharp cheese, grated