Put a deep frying pan or wok filled with water on to boil. Peel and grate the garlic and ginger. Halve the chilli. Flick out the seeds and white bits for less heat. Finely chop it. Finely grate the zest from the lime. Pop all of these in a bowl and set aside.
Trim and peel the carrot. Slice it into finger length batons. Peel and finely slice the shallots. Separate the pak choi leaves. Finely chop the stalks and shred any really large leaves. Drain the tofu and chop into bite-sized pieces.
When the water is boiling, add 2 bundles of the noodles to the pan. Simmer for 3 mins, then drain and tip into a bowl. Cover with cold water to stop them cooking and set aside for later.
Wipe the pan dry and set over a high heat. Warm for 1 min, then add 1 tbsp sunflower or olive oil. Add the garlic, ginger, chilli, lime zest and lime leaves. Stir fry for 1 min.
Add the shallots, carrot and pak choi stems to the pan. Stir fry for 5 mins till the veg have softened a little. Add the tofu to the pan.
Pour the coconut milk into the pan. Swirl in the tamari. Add 400ml boiling water. Cover and bring to the boil. When boiling, turn the heat down a little.
Add the pak choi leaves to the pan. Simmer for 3-4 mins to wilt them. Add the noodles and swirl everything together to mix. Heat through for 1 min. Ladle the broth into bowls and serve straight away.