Preheat the oven to 160°C.Heat the oil in a large, deep roasting pan or a large casserole dish and brown the lamb until brown all over. Be patient.Remove the lamb from the pan and set it aside.
Now, in the same casserole dish, add the onions, carrots, celery and soften them for a few minutes. Next add in the garlic, rosemary, wine and a little salt and pepper.Cover with a lid or cover the whole pan with foil Roast the lamb for 3 – 4 hrs until the meat is tender and starting to fall off the bone.
**About an hour before serving, remove the pan from the oven and skim off any excess fat. Check the seasoning of the braising liquid and season with salt and pepper.When ready, check the seasoning, and serve with dauphinoise