Make the tomato sauce: in a large deep frying pan or skillet over medium-high, heat two tablespoons of a neutral cooking oil until shimmering, sauté the garlic for a minute until fragrant, add the can of diced tomatoes and pork stock and cook for 5 minutes. Add the caster sugar, fish sauce, soy sauce, rice vinegar, and pepper, stir to incorporate, and reduce the heat to low to simmer.
Make the meatball mixture: to a mixing bowl, add the fatty minced pork, finely diced onion and jicama, minced garlic, fish sauce, soy sauce, and white pepper. Use your hands to combine loosely. Taste by rolling a teaspoon of the pork mixture into a small meatball and microwaving or frying until cooked; taste and if needed, adjust the seasoning to suit your palate.
Form the meatballs: use an ice-cream scoop or tablespoon to scoop out a heaped spoonful of pork mixture, roll it between your two hands a few times to roughly form a 5cm-diameter ball, set it down on a tray and repeat. You should end up with around 20 meatballs.
Cook the meatballs: in a flat-bottomed wok or pan, heat three tablespoons of oil over medium heat under shimmering. Using long tongs, transfer the meatballs to the oil so they’re not touching and fry, turning occasionally, until golden brown.
As the meatballs turn golden-brown, use the tongs to transfer them to the pan of tomato sauce and simmer for 15 minutes or until ready to eat.
Sprinkle on fresh coriander leaves and serve in the pan at the centre of the table or distribute amongst bowls. Serve with more fresh herbs and sliced chillies and baguettes for dipping and scooping.