Heat 1 tablespoon of the oil in a wok or large frying pan until starting to smoke, add the tofu and stir-fry over a high heat for 2 minutes until golden. Remove from the pan with a slotted spoon.
Heat the remaining oil in the pan, add the onion and carrots and stir-fry for 1½ minutes. Add the broccoli and red pepper and stir-fry for 1 minute, then add the courgette and sugar snap peas and stir-fry for 1 minute.
Combine the soy and chilli sauces and measurement water and add to the pan with the tofu. Cook for 1 minute. Serve in bowls, garnished with chopped red chillies and basil leaves.