Season the ground pork with pepper, salt, tapioca starch, chopped shallots, minced garlic, and sugar. Mix well and let marinate for 30 minutes. Then form into round meatballs.

Heat a pressure cooker with some cooking oil and sauté the chopped onion until fragrant. Add the pureed tomatoes, then stir in the tomato ketchup, fish sauce, salt, and sugar to taste. Bring to a boil, add the meatballs, and pour in enough hot water to just cover the meatballs. Close the lid and simmer on low heat for 20 minutes.