Oddly enough, turkey is a popular meat in Umbria, and there it is raised to have some flavour. Legs and breasts are sold separately.
You would be unwise to tell your dinner guests the English translation of this dish before they taste it. This is an Umbrian adaption of the North Italian speciality, Vitello Tonnato. This substitution crops up a lot round Orvieto; turkey breast is roasted with rosemary like veal rump, escalopes of fillet are breaded and fried like Scallopini di Vitello, the legs are braised in red wine. Anything at all except roast the whole bird: the Italians are too canny with their ingredients, clever enough to always butcher a large bird and use the different parts to their best advantage. The part of the recipe devoted to roasting the breast makes a delicious hot dish without the tuna sauce, perhaps a hot dish one day then cold the next. Sounds like Christmas?
The turkey breast should be boned, skinned and not stuffed. If you get one from the supermarket, untie it and remove the stuffing and skin, re-tie and proceed.