Rinse the rice thoroughly then put them in a pot. Add 3 cups of water, then bring to the boil over high heat. Don’t cover the pot!
When the surface of the rice is moon-like and bubbly, turn down the heat to very low, cover the pot and cook for 6 minutes. Turn off the heat, and rest the rice for 10 minutes under cover.
Meanwhile, cut the onion into thin slices. Finely chop the garlic.
Heat the oil in a large frying pan and gently sauté the onion. Add the garlic and stir-fry for 30 seconds.
Add the lentils and vinegar, the stir for a minute. Add the kale and the stock.
Cover and cook for 5 minutes, then fold in gently the rice. Add more stock if it’s too dry - it should be moist but not stew-like. Season to taste.
Mix in the chopped herbs, then serve.