Chicken Rice Casserole

Ingredients

• 1 cup uncooked long-grain rice
• 1/2 cup chopped onion
• 1/4 cup olive oil (original recipe called for melted margarine)
• 2 1/2 cups chicken broth (use low-salt bullion)
• 1/2 cup chopped green pepper (~1/2 pepper)
• 1/2 cup diced celery (~1 stalk)
• 1 1/2 to 2 cups cut-up cooked chicken (~2 breasts)
• 1/2 cup sliced mushrooms
• 8 very thin slices of cheddar cheese