Soak the dried mushrooms in boiling water for 30 mins, then drain, reserving the liquid, and squeeze out any excess water. Remove and discard the stems and cut the caps in quarters.
Heat a wok over high heat, add the oil and heat until very hot. Stir-fry the mushrooms and bamboo shoots for 1 minute.
Add the snow peas and quick stir-fry for a futher 1 minute. Add the soy sauce and sugar, stir a few times, then add 100ml of the reserved liquid. Bring to the boil and braise for 2 mins, stirring constantly.
Combine the cornflour with enough water to make a paste, add to the sauce and simmer until thickened. Sprinkle with the sesame oil, blend well and serve with rice.