Grilled Three Cheese Potatoes
["6 large potatoes, sliced 1/4-inch thick", "2 medium onions, chopped", "1/3 c. grated Parmesan cheese", "1 c. shredded sharp Cheddar cheese", "1 c. shredded Mozzarella cheese", "1 lb. sliced bacon, cooked and crumbled", "1/4 c. margarine, cubed", "1 Tbsp. minced fresh or dried chives", "1 to 2 tsp. seasoned salt", "1/2 tsp. pepper"]
["Divide the potatoes and onions equally between two pieces of heavy-duty foil that has been coated with nonstick cooking spray."]
["potatoes", "onions", "Parmesan cheese", "Cheddar cheese", "Mozzarella cheese", "bacon", "margarine", "chives", "salt", "pepper"]