1. For the stuffing, sauté onion and mushrooms about five to 10 minutes, until soft and most of the liquid has evaporated. Add mushroom mixture, spinach, and spices to mashed potatoes. Mix well and stuff into “pocket” of veal breast.
2. Rub the meat with olive oil, kosher salt, black pepper, paprika, and garlic powder (or garlic). Place into a 9×13-inch pan. Surround meat with potatoes. Sprinkles potatoes with salt and pepper.
3. Preheat oven broiler to high. Place pan on top shelf and broil for eight minutes. Remove from oven and preheat to 350 degrees Fahrenheit. Cover pan tightly and bake for three hours. Cool completely before slicing.