Tip the rice into a bowl and cover with cold water. Whisk for 1-2 mins till the water goes cloudy. Drain the rice, rinse under cold water and tip back into the bowl. Cover with fresh cold water and set aside to soak.
Peel and chop the onion. Heat a pan for 1 min. Add ½ tbsp oil and the onion. Season. Cook for 5 mins till just soft, stirring occasionally. Peel and grate or crush the garlic. Halve the chilli and flick out most of the seeds, keeping in a few for a bit of heat. Finely chop it.
Add 2 tsp coriander seeds to the pan. Cook and stir for 1 min. Add in the lamb, breaking up the mince with a wooden spoon. Stir for 5 mins till the lamb has browned. Pour in the chopped tomatoes. Stir and season again. Pop on a lid and simmer for 15 mins till the sauce has reduced.
Drain the rice and rinse again. Tip into a small pan. Add 400 ml boiling water, the cinnamon stick and a pinch of salt. Cover and bring to the boil. Turn the heat down very low and simmer for 8 mins till all the water is absorbed. Set aside, lid on, for 5 mins to finish cooking the rice.
When the chilli has cooked for 15 mins and the rice has been set aside, drain and rinse the kidney beans. Tip in to the chilli. Put the lid back on and cook for a further 5 mins.
Pick the leaves from the coriander. Finely chop the stalks and stir into the chilli. Taste and add more salt and pepper if you think it needs it.
Take the cinnamon stick out of the rice. Fluff it up with a fork. Spoon it into bowls and top with the chilli con cordero. Garnish with coriander leaves to serve.