Take some thickly cut shoulder lamb chops, one or two per person depending on whether you are serving other courses and the appetite of your dinner companions. Bone and trim the chops of excess fat. (NB: Don't try to remove all the fat, just the really thick swaths of it. You want some fat to moisturize the meat during its rather long cooking time.) Cut the meat into cubes and add to a large mixing bowl. Then add a healthy splash of white wine, a pour of olive oil, one medium sliced onion, fresh rosemary, salt and pepper, and mix the ingredients well. If you have the time, allow the meat to marinate in this mixture for at least an hour and up to a day ahead.

When you are ready to cook, add chunks of potato, about the same size of the lamb cubes. Use as much potato as you like; I find that a 1:1 ratio of potato to lamb meat by weight produces a fine result. Mix the potatoes and lamb meat, then pour the entire mixture into a baking dish large enough to hold it all without it coming, say, any more than 5cm (3 in) up the sides of the dish.

Bake in a hot oven (200°C, 400°F) for about a half an hour covered, then remove the cover, raise the heat a bit and allow the casserole to continue cooking until the lamb and potatoes are tender and nicely browned, about 30 minutes more. The lamb will have shed quite a bit of water in the first half of cooking; the liquid should evaporate, but not quite completely, by the time it is done. Mix the lamb and potatoes from time to time to baste and allow the pieces to cook evenly, but leave the dish alone for the last 15 minutes or so, so a nice brown crust forms on top. If you find that the lamb has given off a lot of grease, you can skim the excess off with a spoon but, once again, do not skim all of the fat off, as it provides both moisture and flavor.

When the dish is done, remove it from the oven and allow it to cool and settle for a few minutes before eating. It can be made ahead and re-heated as well, and only improves if you do so.