Using a mortar and pestle, pound the garlic cloves and 1 knob of ginger into a paste, then transfer to a mixing bowl, along with the fatty pork mince, fish sauce, white pepper, and sugar. Combine well, then refrigerate until ready to use.
Pound the other knob of ginger and lemongrass in the mortar and pestle just until they break and their aromas are released, then add them to a medium-sized soup pot with a litre of water. Turn the heat to high and bring to the boil.
Once the water is boiling, add the leftover cooked jasmine rice, stir, and reduce the heat to low. While the rice soup is simmering, prep your garnishes, then form the seasoned pork mince into mini meatballs. Keep an eye on the rice soup, stirring occasionally so it doesn’t stick and if necessary, adding more water to the pot.
Make the mini pork meatballs by using a teaspoon to scoop out the mince and gently roll it between two hands to shape into a small ball of around 2cm in diameter. Once you’ve finished making all the pork balls, gently submerge each one into the rice soup and continue to simmer for another 10 minutes or until the pork meatballs are just cooked.
Ladle the rice soup into bowls and serve immediately, as is – along with plenty of fresh herbs and condiments, such as fish sauce, chilli oil, fried shallots, and fried garlic.