Season the flour with salt and pepper and use to coat the meat. Heat the oil in a flameproof casserole and fry the pieces of meat on all sides until browned. Drain.
Add the onions to the pan and fry gently for 5 minutes. Add the garlic, prosciutto and strips of lemon rind and cook for 1 minute. Add the wine and thyme sprigs and bring to the boil.
Return the veal to the casserole and tuck the tomatoes around. Scatter with the capers and cover with a lid. Place in a preheated oven, 160°C (325°F), Gas Mark 3, for about 2 hours until the meat is very tender. Check the seasoning and serve.