Preheat the oven to 160C / 140C fan / gas mark 3 / 325F.
Drizzle 2 tablespoons of olive oil into a wide, deep saucepan or hob proof casserole dish and add the sliced onion, cinnamon stick, bashed cardamom pods and cloves. Cover with a lid and cook on a low heat for 5-10 minutes until the onions have softened but are not brown.
Add in the crushed garlic, ginger, chilli flakes, cumin, coriander, turmeric and garam masala. Stir and fry uncovered on a low heat for 3 more minutes.
Add in the chopped lamb and stir to coat the lamb in the spices. Continue cooking for a couple of minutes to allow the lamb to start cooking.
Add in the tinned tomatoes, 100ml water and salt. Stir and bring to the boil.
If you are using an ovenproof saucepan or casserole dish, simply pop the lid on and put it in the oven for 1 hour and 15 minutes.
If you are using a saucepan that cannot go in the oven (e.g. one with a plastic handle!), transfer the curry to an oven dish / Pyrex dish, put the lid on and pop it in the oven for 1 hour and 20 minutes. (It gets an extra 5 minutes, as the oven dish will be cold, so will slow down the cooking process to begin with.)
Don’t forget to make some rice 10-30 minutes (depending on your recipe) before the curry is due to come out of the oven.
Just before serving the curry, add a large handful of coriander leaves to the curry and stir. Serve scattered with more coriander leaves and with some rice and a beer or a glass of red wine. Enjoy!
Nutrition information is approximate and meant as a guideline only.