Put three-quarters of the coriander (leaves and stalks), the fish sauce, sugar, garlic, ginger, shallots or onion, and zest and juice of 1 lime into a blender and blitz to a fine paste, adding a splash of water if you think it is necessary.
Put the prawns in a bowl and sprinkle over the cornflour. Season and toss together until well coated.
Heat the sunflower oil in a deep frying pan and add the ginger paste. Fry for 3 minutes, then add the prawns and cook for 2–3 minutes or until just pink.
Add the noodles and carrot, and toss everything together. Cook for 2 minutes until heated through.
Remove the pan from the heat and set aside a quarter of the mixture. Slice the remaining lime into wedges. Divide the noodles between serving bowls and garnish with the peanuts, lime wedges and remaining coriander leaves.