1. Peel, rinse and mince water chestnuts.
2. Rinse and mince celery; Rinse and discard the stems of coriander.
3. Rinse spring onion; Mince the majority; Dice the remaining.
4. Whisk egg.
5. Rinse ground pork; Marinate in seasonings for 1 hour; Add minced water chestnuts, minced celery, minced spring onion and egg; Mix well by stirring in one direction; Slap the mixture hard to the cutting board for at least 10 times to be the filling.
6. Add some potato starch and some water in a bowl; Mix