For the lamb, preheat the oven to 120 degrees Celsius. Take a large casserole dish (large enough to fit the whole leg of lamb and put the lid on) and place on the hob on a medium heat. Brown the lamb on all sides – you shouldn’t need any oil, but if it starts to stick add a little olive oil.
Throw in the thickly chopped onions, peeled (but not sliced) cloves of garlic, bay leaves, rosemary, thyme and red wine. Put the lid on and put in the oven for 5 hours, checking every so often that it’s not catching.
For the potatoes, peel and thinly slice the potatoes and garlic cloves. Layer potato and a sprinkling of garlic until all are used, then pour over the cream and top with the cheese. Put in the oven with the lamb for 1 hour and 30 minutes.
When the lamb and potatoes are done, remove from the oven and set aside. To make the gravy, carefully remove the lamb from the casserole dish (it will try to fall apart!). Rest the lamb for 20 minutes. Put the casserole dish containing all of the cooking juices on the hob and stir in the red wine. In a small cup, mix the flour with a few drops of cold water then stir into the gravy until it thickens. Enjoy!