Cheddar Cheese Soup

Ingredients

• Vegetable cooking spray
• 1 teaspoon margarine
• 1 cup finely chopped onion
• 1 cup finely chopped celery
• 1/2 cup nonfat sour cream
• 1/4 cup plain low-fat yogurt
• 1/3 cup all-purpose flour
• 2 (10 1/2-ounce) cans chicken broth undiluted
• 3/4 cup skim milk
• 1 teaspoon white wine Worcestershire sauce
• 1/4 teaspoon garlic powder
• 1/8 teaspoon salt
• 1/8 teaspoon ground white pepper
• 1/8 teaspoon ground red pepper
• 6 (2/3-ounce) slices low-fat process Cheddar cheese