Warm the Chicken broth in a saucepan and add the Saffron threads to bloom while you prepare the rice.
In a wide pan, melt Unsalted butter with a little Extra-virgin olive oil, then gently sweat finely chopped Onion until translucent.
Add the Arborio rice to the pan and toast for 1–2 minutes, then deglaze with the Dry white wine and let it absorb.
Ladle the hot saffron broth into the rice, a cup at a time, stirring frequently until the rice is creamy and al dente; finish by stirring in grated Parmesan (Parmigiano Reggiano), a beaten Large eggs to bind, and season with Salt and freshly ground Black pepper. Spread the risotto on a tray to cool completely (chill briefly so it’s easier to handle).
Meanwhile make the ragù: render diced Pancetta in a skillet, add finely diced Carrot, Celery and a little more Onion and cook until softened.
Add the Ground beef and brown, then stir in Tomato paste, a splash of the Dry white wine to deglaze, and the Tomato passata. Simmer until thickened, fold in Peas, and adjust seasoning with Salt and Black pepper. Let the ragù cool.
To assemble, wet your hands and take a handful of chilled risotto, flatten it in your palm, place a teaspoon of ragù and a cube of Mozzarella (fior di latte) in the center, then close and roll into a compact ball.
Set up a breading station and coat each ball first in All-purpose flour, then dip in the remaining beaten Large eggs, and finally roll in Fine breadcrumbs to form an even crust.
Heat enough Extra-virgin olive oil (or neutral oil if preferred) in a deep skillet or fryer to 175–180°C (350–360°F) and fry the arancini in batches until deep golden and crisp on all sides, about 3–4 minutes.
Drain on paper towels briefly and serve the arancini hot so the mozzarella inside is deliciously gooey.
