To prepare the vegetables either peel and grate coarsely (for root vegetables such as carrots, celeriac, turnip, swede) or slice finely (Brussels sprouts, cabbage).
Rinse the rice in cold water and then put in a pan with 300ml boiling water. Bring back to the boil, cover with a lid, turn the heat down as low as it will go and leave to simmer gently for 15 minutes. After 15 minutes, turn the heat off and leave it to steam with the lid on.
While the rice is cooking, finely chop the red onion, heat the oil in a large frying pan and add the onion and chilli flakes. Fry over a medium heat for about 5 minutes, stirring occasionally.
Add the crushed garlic and fry for another minute or two.
Add the prepared vegetables and fry over a fairly high heat for 8 minutes. Don't stir too often because you want to get a bit of colour on them.
Add the tomato puree, kecap manis, soy sauce, white wine vinegar and sesame oil. Stir well and cook over a low to medium heat for a further 5 minutes.
Add the cooked rice into the frying pan and mix in with the vegetables, continuing to cook for a couple more minutes.