Heat the oil in a large frying pan over a medium heat and fry the shallot, lemongrass, garlic and chilli for 3 mins until fragrant. Add the pork mince and stir-fry for about 10 mins more until the pork is cooked through and browned. Add the fish sauce, sugar and lime juice, and cook for a couple more minutes until the pork is coated in the mixture. To freeze, leave to cool completely, then transfer to a freezer bag, seal and lay flat in the freezer (so the mince stays in a thin layer). Will keep for up to two months. Defrost in the fridge overnight before using. Reheat in a dry frying pan over a low heat until piping hot.

Add the pork mince and stir-fry for about 10 mins more until the pork is cooked through and browned. Add the fish sauce, dark brown soft sugar, the sweet chilli sauce, the soy sauce and limes, and cook for a couple more minutes until the pork is coated in the mixture.

Make a very simple dipping sauce by mixing the caster sugar with the rice wine vinegar and the remaining bird's-eye chilli. Divide the pork mince between the lettuce leaves and garnish with the spring onions, carrots and coriander leaves and mint leaves, then serve with the dipping sauce on the side.