Slice the cutlets in half and pound each cutlet 1/4-inch thick. Sprinkle each cutlet with salt and pepper on one side only; do not salt the side the prosciutto will be on or it will become too salty. Using a toothpick, secure a slice of prosciutto and a sage leaf on top of each cutlet.
Add the flour to a plate, sprinkle with salt and pepper and whisk together. Dredge each cutlet through the flour, shaking to get rid of the excess flour.
In a 12-inch skillet, melt the butter in the olive oil over medium-high heat. Then add 4 cutlets, prosciutto-side down, into the pan. Cook about 3 minutes on each side. Add the wine to the skillet and cook until the sharp smell of the wine is cooked off, about 3 minutes. Repeat with the remaining cutlets using a clean skillet. Serve the cutlets on a large platter and drizzle with the sauce. Garnish with fresh sage.