Place the mushrooms in a bowl and cover with warm water. Leave to steep for around 30 minutes.
Place the rice in a heavy-based saucepan. Add the water and season with salt and pepper. Bring to the boil, cover, lower the heat and cook for around 15 minutes. Take the pan off the heat and stand, covered, for about 10 minutes. Fluff up the rice by stirring it with chopsticks.
Meanwhile, cut the green beans into 4 cm (1½ inch) slices. Break the broccoli into florets. Rinse and drain them. Drain the mushrooms well, remove the stalks and slice the caps finely.
Heat the oil in a wok. Stir-fry all the vegetables for 3–4 minutes. Season with salt and pepper, then sprinkle with the grated ginger. Serve with the hot rice.