Finely slice the spring onions and garlic. Cut the mushrooms into chunks and the bell pepper into thin slices.
Heat the oil in a wok over medium-high heat. When it’s hot, add the spring onion and stir-fry for 3 minutes, then add the garlic and chilli flakes and stir for another 30 seconds.
Add the mushroom and red pepper, stir fry for a minute or so, then add the soy sauce, sesame oil & seeds. Add some lime juice too. Turn down the heat and sauté for 3-5 minutes, until the mushrooms and red pepper are tender.
Scatter the coriander leaves on top, season with plenty of ground pepper and squeeze some lime juice over it, then serve.