Place the dried mushrooms in a small heatproof bowl, pour over the measurement water to cover and leave to soak for 30 minutes until softened. Drain and reserve the soaking liquid. Remove and discard the stems, and dice the caps.
Heat a nonstick wok or frying pan over a high heat, add the oil and heat until almost smoking. Add the ginger, shallots and diced mushrooms and stir-fry for a few seconds.
Add all the seafood and stir-fry for about 2–3 minutes until the prawns are just beginning to turn pink. Add the cooked rice, reserved mushroom soaking liquid and stock and bring to the boil.
Stir in the rice wine and soy sauce and season to taste with salt and white pepper. Add the pak choi and coriander and gently simmer for 6–8 minutes until the seafood is cooked through and all the mussels have opened, discarding any that remain closed. Serve immediately, ladled into warmed bowls.