Melt butter in large saucepot, add onion and garlic and sweat till translucent.
Stir in arborio rice and toast, while stirring, till aromatic and rice is starting to cook, 3-5 minutes.
Add white wine and bring to a boil then simmer for a couple minutes.
Meanwhile, warm the stock in a separate pan.
Ladle the stock into the rice over medium heat, stirring the entire time until the stock is absorbed, then add another ladle until all the stock is used, 20-25 minutes. Make sure it is creamy and most of the liquid is absorbed.
Stir in parmesan and season with salt and pepper.
Spread over a baking tray to cool quickly, press plastic wrap to the top, and store in the fridge until very cold.
Warm about 2 inches canola or peanut oil in heavy-bottomed saucepan over medium heat.
Set up the eggs, flour, and breadcrumbs in separate bowls.
Shape the rice mixture around the mozzarella pieces to form 15-18 balls.
Then dredge the balls in flour, dip into the egg mixture, and finally in the breadcrumbs.
Deep fry for 2-3 minutes until golden brown. Remove and drain.