Lay the cutlets flat on a clean, dry work surface. In a small bowl, mix the cheese and prosciutto. Evenly divide this mixture among the 4 cutlets, placing the mixture in the center of each cutlet. Season with salt and pepper. Fold in half being careful that none of the cheese and prosciutto stuffing escapes. Secure sides with toothpicks. Dredge rolls in flour.
Heat a 12-inch saucepan over medium-high heat. Add the 3 tablespoons of butter and cook until the butter foams. Add the veal rolls to the pan and brown on all sides, about 5 minutes per side. Use tongs to carefully turn the rolls. Remove rolls and keep warm. Add the sage leaves to the pan and pour in the wine. Continue cooking over high heat until the wine evaporates. Swirl in the remaining 1 tablespoon of butter. Serve immediately with a sprinkling of Emmental cheese on top.
Recipe courtesy of Mario Batali