To the mince, add the finely chopped onion, soya sauce, rice wine, salt and egg yolks. Knead well and make small balls to then roll in the starch.
Fry the balls in hot vegetable oil until they brown. Add the pineapple juice, sugar, and vinegar to the oil and once they come to a boil, add 1 tsp starch. Wait for the sauce to thicken slightly.
When serving, pour the sauce over the fried meatballs.