Heat up cooking oil in a soup pot and fry the Sichuan peppercorn over slowest fire. Place ginger and scallion in and fry until aromatic. Add 3-4 pieces of lamb in and slightly fry for 1 minute.
Add winter melon and water, simmer for 15 minutes or until the winter melon becomes soft. Place the remaining lamb pieces in and season with white pepper and salt.
To serve the soup: serve with green onions and corianders. Add a small grasp of green onion and coriander in the bottom of the serving bowls and then scoop the soup in.
To serve the lamb slices: mix the spices and serve as a dry dip.