Heat the oven to 150C (130C fan).

Put the flour in a bowl and season heavily with salt and pepper. Dust the lamb shanks in the seasoned flour.

Place a heavy casserole pan on the hob on a medium heat and throw in the butter and a little oil. Once the butter is beginning to foam, add the lamb shanks to the pan (do it in batches if you need to) and brown on all sides - it should take 5-10 minutes per batch. Once they're done, remove them from the pan and set aside.

Add the onions and garlic to the pan and cook for 3-4 minutes until softened. Then, remove them from the pan and put them with the lamb shanks.

Put the tomato puree in the pan and fry for 30 seconds, then add the wine and vinegar. Bring the liquid to the boil, scraping the bottom of the pan to get all the tasty brown stuff!

Add the lamb and onions back to the pan along with the rosemary. Put the lid on the pan and then bang it in the oven for 2 hours and a half hours.

At the end of the cooking, if the red wine gravy looks too thin (it probably will), remove the shanks from it (And keep them warm) and place the pan back on the hob and boil vigorously until the desired thickness is reached.

Serve! Goes great with mashed potato and french beans!