*The reason why you want to line your grill pan or you grill grates with aluminum foil is because we are adding adding butter while it is cooking and if butter drips into the grill, it can cause flare ups and you don't want to burn your potatoes. *You could also just line your grill gates with aluminum foil instead of the pan itself. Do this before turning on and preheating your grill. *Alternatively, you could set your grill pan over indirect heat so as not to cause flareups if you don't line the pan with foil. *If you don't want to line anything with aluminum foil, you don't have to. You can add the 4 tablespoons of butter to the hot vegetables after you take them off the grill and stir to combine. Just make sure to spray your grill basket with nonstick cooking spray.