Peel and grate or crush the garlic. Peel and finely chop the shallot. Grate the zest from the lime. Rinse and halve the chilli. Finely chop it.
Put the garlic, shallot, lime zest and half the chilli in a bowl with the beef mince. Add a pinch of salt. Knead together. Shape into small, flattish meatballs. Pop on a plate. Freeze for 10 mins.
Juice the lime. Mix the lime juice with the remaining chilli, half the sachet of tamari and 1 tbsp of the Demerara sugar. Pop to one side.
Fill a pan with water. Add a pinch of salt. Bring to the boil. While the water is simmering, separate the largest lettuce leaves and rinse them. Pat them dry with kitchen paper.
Warm 1 tbsp olive oil in a frying pan. Add the meatballs. Fry for 2-3 mins. Flip them over. Cook for 2-3 mins till they’re cooked through. You may need to do this in batches (see our tip below).
Add the noodles to the pan of boiling water. Simmer for 3 mins till they are just soft. Drain them. Tip them back into the pan. Mix them with ½ tbsp olive oil.
Pile the meatballs and noodles into the lettuce leaves. Spoon over the sauce. Serve straight away.