To chiffonade the sage, tightly roll the leaves horizontally into a cigar shape. Then slice it end to end to produce little ribbons.
Pound the veal cutlets to thin them out and season with salt and pepper.
Evenly distribute the sage over the cutlets and then top each with a slice of prosciutto.
Fold the cutlets in half and pound them again to a uniform thickness.
Melt half the butter in a large skillet. Place the veal packets in the pan, brown the first side, flip and repeat. Remove the veal and reserve.
Add the wine and deglaze the pan, scraping the browned bits off the bottom.
Add the remaining butter.
Season with salt and pepper.
Return the veal to the pan and very briefly cook it on each side just to coat it with the sauce and serve.