Cook the egg noodles according to packet instructions. Meanwhile, heat the vegetable oil in a wok or frying pan and fry the tofy until crisp and golden. Remove with a sloted spoon and set aside.
In the same pan, stir-fry the chopped onion with the peppers for about 10 mins or until soft. Stir in the 3 tbsp each of soy, sweet chilli and hoi sin sauces, then return the tofu to the pan.
Drain the cooked noodles and add to the pan along with the sesame oil. Stir-fry until hot and then serve.