1. Preheat oven to 375 degrees.
2. Combine mozarrella, prosciutto, parmagiano-reggiano and parsley in a bowl and mix well.
3. Place a tablespoon of the mixture on each scalloppine, roll up and fasten with toothpicks.
4. Heat olive oil in a large oven-proof saute pan over medium-high heat.
5. Dredge the rolled up veal in flour, shaking off the excess and place in pan.
6. Brown quickly on all sides, then place the pan in the oven.
7. Cook for about 10-15 minutes, turning once, until veal is cooked through and the cheese is melted.
8. Remove pan from oven, transfer veal to a plate and cover loosely with aluminum foil.
9. Drain the oil from the pan, place over medium heat and add the butter and mushrooms.
10.Saute the mushrooms until they begin to release their juices.
11.Add the white wine to the pan, and scrape loose with a wooden spoon all browning residues on the bottom and sides of the pan.
12.Cook until the wine is reduced by half, then add the chicken broth and season with salt and pepper to taste.
13.Return the veal to the pan and cook until sauce is reduced by half and thickened.
14.Transfer the rollattini to warm serving plates, spoon sauce and mushrooms over and serve.