Put the chopped spring onions (reserve a handful of the green part for the garnish) in a bowl with the beef and pork mince, grated ginger, egg, sesame oil and pinch of salt and white pepper.
Start adding the cornflour, little by little, kneading the mixture well for a few minutes until doughy and elastic.
Scoop portions of the meat mixture with a teaspoon to make bite-sized balls.
Make sure all the meatballs are the same size to ensure consistent cooking times. Dust them lightly in cornflour.
Pour enough oil to come up to about 1cm deep in a large frying pan and set over medium heat.
Once the oil reaches about 160 degrees C, drop the meatballs carefully into the pan. Shallow-fry them by turning them in the oil until they are just cooked — 3 to 4 minutes depending on the size of the meatballs.
Alternatively, for a healthier option, bake the meatballs with a drizzle of oil in an oven preheated to 180° C for 12-15 minutes on a try lined with scrunched baking paper.
While the meatballs are cooking, squeeze the juice from the grated ginger into a small bowl along with the other ingredients for the sauce and mix well until there are no lumps.
Heat a large frying pan and add the cooked meatballs. Once the pan becomes very hot, pour in the sauce mixture, shake the pan from side to side to coat the meatballs well and let the sauce thicken, about 1 minute.
Transfer to large shallow bowls, sprinkle with the finely chopped spring onion greens and finish with the toasted sesame seeds sprinkled on the top.