Many versions of dumplings are wrapped in leaves - banana, bamboo, pandan or lotus, as in this recipe. The leaves help the filling to steam and impart a subtle aroma when you unwrap them.
Note Lotus leaves, lap cheong and salted duck eggs are available from Chinese grocers. If lotus leaves aren't available, substitute blanched Chinese cabbage, though you won't get the same fragrance. Lap cheong are dried Chinese pork sausages that don't need refrigeration after opening.