In a large mixing bowl, combine your cooled leftover risotto with salt, pepper, and Parmesan cheese. Stir thoroughly until nicely blended.

Using your hands, take about a tablespoon of the risotto mixture, flatten it, place a cube of mozzarella in the center, and roll into a ball.

Prepare your coating station with flour, beaten eggs, and breadcrumbs.

Roll each ball in flour, dip in eggs, then coat with breadcrumbs. Place on a tray.

Cover the tray with plastic wrap and refrigerate for at least 20 minutes.

Heat oil in a deep frying pan to about 350°F (175°C). Fry the rice balls in batches for 3-4 minutes until golden brown.

Transfer the arancini to a paper towel-lined plate to absorb excess oil.

Serve warm with marinara sauce for dipping.