If your lettuce wrap feels difficult to fold, use two large iceberg leaves overlapping slightly to create a stronger base. Iceberg works best as it’s crisp and sturdy, whereas softer lettuces can tear more easily. Wrapping the finished burger tightly in parchment or baking paper helps hold everything together and makes it easier to eat. If your patties seem slightly large for the lettuce leaves, simply trim the edges of the patties with a spatula or break them slightly when stacking so the wrap closes neatly.