To prepare your arancini, cook the rice in plenty of salted water for 15 minutes. When cooked, drain the rice and add an egg. Add the grated Pecorino Toscano and Pecorino Romano cheese; mix and blend everything together. Then let it cool for about an hour. When the time is up, take a portion of rice with a spoon, place it on the palm of your hand and fill the center with a few cubes of provolone. Now shape the arancini into rather large meatballs and dip them first in beaten egg, then in breadcrumbs. Fry them in plenty of hot oil until they are golden brown on all sides. Serve the rice balls hot.