Mince (grind) the pork and mix in the soy sauce and sherry.
Chop the spring onion (scallion) finely and add to the pork with the sesame oil, cornflour (cornstarch) and salt.
Beat well until blended.
Mix the flour and hot water together to make soft dough, adding more water if necessary.
Divide the dough into 24 pieces and shape each into a ball.
Make a hole in the centre of each ball and press some of the pork filling into the middle.
Shape the dough around the filling and pinch the edges together.
Drop the balls into a large pan of salted boiling water; allow coming back to the boil and boiling for 5 minutes.
Add 1/2 pint cold water to the pan, bring back to the boil and boil for another 3 minutes.
Drain the balls and serve four or more to each person with a little of the boiling water.
Use a spoon to eat the balls, in order to catch the juices from the centre as the first bite is taken.