Chop the pork fairly finely and fry it in the oil for under a minute, tossing it about.
Add the soy sauce, seasonings and 1/2 teaspoon of cornflour, blended with the water, and cook, stirring, for 1 1/2 minutes. (This is a rather dryish mixture.)
Set aside to become cold.
Mix together the remaining cornflour and the oyster sauce and add to the meat.
Divide the mixture into 5 equal portions.
TO MAKE THE DOUGH Turn the flour, baking powder and sugar on to a pastry board.
Make a hole in the centre.
Pour the oil and water into it and gradually mix together with the handle of a wooden spoon.
Gather up the dough and knead it very well, using the heels of the hands, until it is very firm.
Divide into 5 balls and flatten each into a round 1 1/2 inches in diameter.
Place one round of dough in one hand.
Add a portion of the filling and bring the outer edges together and pinch them with the thumb and forefinger of the other hand (see photograph 1).
Continue this pinching and shaping all round to form the dumplings
Place each dumpling on a square of greaseproof paper and steam for 20 minutes.