Place the rice in a heavy-based saucepan. Add the water and season to taste. Bring to the boil, then cover. Lower the heat and cook for around 15 minutes. Take the pan off the heat and leave it resting, covered, for about 10 minutes. Aerate the rice by stirring it with chopsticks.
Top and tail the mangetout, removing any stringy bits. Rinse and drain, then cut them in half. Peel and grate the carrots. Pick over the bean sprouts, wash them in cold water and drain. Peel and finely chop the garlic.
Heat the oil in a wok. Quickly stir-fry the garlic and ginger then add the mangetout, carrots and bean sprouts. Stir-fry for 2–3 minutes then add the soy sauce, caster sugar and warm water. Cover and leave to simmer for 3 minutes.
Serve the vegetables with the hot rice.