Make the risotto and let cool completely or overnight
Using a small ping pong ball-sized scoop, scoop the chilled risotto into the palm of your hand. Stuff with a cube of the cheese and make sure it is completely covered.
Pulse the panko breadcrumbs in a food processor or place in a zip top bag and crush up finely with a rolling pin.
Transfer breadcrumbs to one of three shallow bowls. Place the flour in another shallow bowl and lightly beat the eggs in a third shallow bowl. Working one at a time, dredge the risotto balls in the flour, then the egg, then the breadcrumbs. Coat them completely.
Chill the balls until the oil heats up.
Make the pesto aioli while the risotto balls chill down and the oil heats up. In a small bowl, whisk everything together until well combined and check for seasoning. Chill while you fry the arancini and serve with them on the side.
When the oil is heated to 350 degrees, then you can begin frying the arancini in batches until lightly golden brown and crispy. Garnish with freshly grated Parmesan and your pesto aioli. ENJOY!