Cover the noodles in a bowl with some boiling water for 3 minutes or until softened, drain.
Heat the oil in a wok or frying-pan, add the onion, capsicum and garlic and stir-fry over high heat for 1 minute. Add the mushrooms and stir-fry for 30 seconds or until softened. Remove from the wok.
Add the mince and stir-fry for 2 minutes or until browned, breaking it up as it cooks. Return the onion mixture to the wok with the soya sauce, chilli sauce and mint. Add the noodles and stir to combine. Serve sprinkled with the peanuts.