Steak and french onion beans

Method

1. Add the butter to a large heavy-based saucepan (one with a lid) over a low heat. Once melted, tip in the onions, then add the thyme and a large pinch of salt. Cover and cook, stirring occasionally, for 40 minutes.
2. Take the lid off and cook for another 40-50 minutes, stirring more regularly, until the onions are a caramel-coloured sticky tangle. Try not to let the onions catch on the bottom – you can add splashes of water if this starts happening before they are properly caramelised.
3. Add the beans and their liquid, then bring to a slow simmer (see Tips). Leave to bubble gently and reduce slightly.
4. Meanwhile, bring a small pan of salted water to the boil and put a large (ideally cast iron) frying pan over a high heat. Season the steaks on both sides with plenty of salt and pepper then, once the pan is smoking, add a dash of oil and the steaks. Cook for about 1½ minutes on each side, depending on thickness. Leave to rest for 3-4 minutes.
5. As soon as the steaks are resting, add the cavolo nero to the boiling water, cook for 3 minutes, then strain and season well. Carve the steaks and stir the resting juices into the beans. Divide the beans between plates along with the cavolo nero, then top with the steaks.