Veal in a Tuna Fish Sauce

This is a great Piedmontese favourite of mine for outdoor summer lunches on those rare occasions when we actually get a summer in England! It is a dish that never fails to create a good impression. I serve it with three or four different salads, including a potato salad and some tender green beans in a vinaigrette dressing. The quantities given below may easily be increased to feed a larger party, but remember that a very big joint of veal easily dries out if roasted whole, so it is best cu