Place the oil in a wok and heat on medium heat for 20 seconds.
Add the garlic. Fry until it becomes fragrant.
Add the prawns and fry until they change colour.
Add the tofu.
Crack the egg straight into the wok. Immediately add the fish sauce and sugar. Stir rapidly until it becomes scrambled. Push this up onto the top of the wok.
Pour the water into the bottom of the wok and add the noodles.
Add the peanuts and the bean sprouts and mix everything together. Keep frying for about another 20 seconds.
Add the spring onions.
When the noodles become dry, switch off the heat and squeeze the lime over the noodles.