Place mushrooms into a large bowl. Combine char sui sauce, sherry, garlic chilli in a small jug & pour over mushrooms. Mix well to coat all mushrooms in marinade. Cover & set aside to marinate for 15 minutes.
Heat a wok over high heat. Add oil, mushrooms & any remaining marinade & stir-fry for 2-3 minutes or until mushrooms are tender.
Add green onions to wok & toss well to combine. Serve mushrooms with steamed rice.