Preheat oven to 250C. Process bread in a food processor until coarse crumbs form, then transfer to a bowl and season to taste.
Place flour and eggs in separate bowls then, working with a piece at a time, dip veal in flour, then egg, then breadcrumbs, pressing veal to coat and shaking off excess in between. Set aside on a tray.
Heat butter and oil in a large non-stick frying pan over medium-high heat, add veal and cook, turning once, until golden brown and almost cooked (3-5 minutes). Transfer to a roasting pan, top with prosciutto and cheeses and bake until golden and cheese has melted (5-7 minutes).
Serve veal parma sandwiched in rolls with lettuce and a little tomato sauce.