Add the Arborio rice and stir to coat in the oil. Toast for 1–2 minutes until the edges become slightly translucent.
Pour in the white wine (if using) and stir until absorbed.
Begin adding the hot stock, one ladle at a time, stirring frequently. Allow each addition to be absorbed before adding the next. Continue for about 18–20 minutes, until the rice is fully cooked but still slightly firm (al dente). It should be creamy.
Stir in the saffron (with its soaking water), butter, Parmesan cheese, salt, and pepper. If using peas or ham, add them now.
Transfer the risotto to a shallow tray or baking dish and spread it out to cool. Cover with plastic wrap (press it directly on the surface to prevent a skin) and refrigerate for at least 3–4 hours, or overnight. This is crucial so the rice firms up enough to shape.
Remove the risotto from the fridge. Take a portion of rice (about 1/4 cup or a golf-ball size) and flatten it in your palm.
Place a cube of mozzarella in the center. Optionally add a bit of ham or ragù.
Carefully wrap the rice around the filling, shaping into a tight ball. Ensure the cheese is completely enclosed.
Repeat with the rest of the risotto and filling.
Set up a breading station: one bowl with flour, one with beaten eggs, and one with breadcrumbs.
Roll each rice ball first in flour (shake off excess), then dip in egg, and finally coat thoroughly in breadcrumbs. Press gently to adhere.
Place on a tray and let rest for 10–15 minutes (helps coating stick better).
Heat oil in a deep pot or fryer to 350–375°F (175–190°C). The oil should be deep enough to submerge the arancini.
Fry the arancini in batches (don’t overcrowd) for 3–4 minutes, turning occasionally, until golden brown and crispy.
Remove with a slotted spoon and drain on paper towels.
Additional notes
You can shape and bread the arancini ahead of time and refrigerate (up to 1 day) or freeze (up to 1 month). Fry from frozen, adding a minute or two to cooking time.
For a lighter version, spray breaded arancini with oil and bake at 400°F (200°C) for 20–25 minutes, turning halfway. They won’t be as crispy but still tasty.
Try stuffing with prosciutto, mushrooms, or leftover ragu. Some versions use tomato sauce inside too.