Cover the rice with water and set aside to soak. Bring a wok or deep frying pan of salted water to a boil.
Halve the cabbage and tear the leaves into bite-size pieces. Finely slice any thick cores. When boiling, add the cabbage to the water and simmer for 5 mins. Drain, rinse under cold water and set aside.
Trim, halve, rinse and finely slice the leek. Thickly slice the mushrooms. Peel and finely chop the garlic and ginger. Finely chop the chillies. Dissolve the stock cube in 500ml boiling water.
Drain the rice and tip into a pan. Add 1 ltr boiling water with a pinch of salt. Cover, boil then turn the heat down. Cook for 10 mins till the water is absorbed, then take off the heat and set aside, lid on, for 5-10 mins.
Warm the wok over a high heat. Add 1 tbsp oil and the mushrooms. Stir-fry for 8 mins till golden brown. Lift out onto a plate. Add 1 tbsp oil to the wok with the leek and cabbage. Stir fry for 5 mins and add back the mushrooms along with the garlic, ginger, chilli, Worcester sauce and vinegar. Stir fry for 1 min.
Add the veg stock to the wok. Cover and simmer for 5 mins. Taste the stock, add a pinch of salt if needed.
Fluff the rice with a fork and spoon into bowls. Divide the stir-fry between them and serve straight away.