Make the meatballs by combining all the ingredients together in a large mixing bowl. Season well and roll tablespoons of the mixture into walnut-sized balls. Place on a tray, cover and chill for 3–4 hours or overnight if time permits.
Place the garlic, shallots, galangal or ginger, chillies and half the oil in a small food processor and blend to a paste.
Heat the remaining oil in a large nonstick wok, add the paste and stir-fry for 1–2 minutes. Add the tomatoes, kecap asin and coconut milk and bring to the boil. Reduce the heat to low and simmer gently for 10 minutes.
Add the meatballs to the curry and simmer for 12–15 minutes, stirring occasionally. Remove from the heat and serve with rice noodles or steamed rice, as preferred. Garnish with sliced red chillies and chopped coriander.