Heat olive oil in a saucepan on low heat.
Add diced onion and cook until translucent, for about 5 minutes.
Then add the cubed pancetta, cook for about 5 minutes.
Add the Arborio rice and stir in.
Stir in the white wine, until the rice absorbs all the wine.
Add the stock a little at a time, stirring until all liquid is absorbed. Keep going until all stock is used and the rice has absorbed all the liquid, stirring continuously for about 30 minutes, until the rice is tender and the has a creamy consistency.
Stir in the peas.
Then add the grated Parmigiano Reggiano and stir in.
Season with black pepper to taste.
Add the dried parsley and stir in.
Transfer from the saucepan to a large baking dish and allow to cool. Once cool either put in the fridge until you need to make the arancini or start to assemble..
Put flour in one bowl, breadcrumbs in the second bowl and the beaten eggs in the third bowl.
Cut the mozzarella into cubes around 2cm (1/2 inch)
Using an ice cream scoop, scoop out the rice to make a ball and stuff a cube of mozzarella inside. Do this until all the rice is used and made into balls
Then one by one roll in the flour, then the beaten egg, and last the breadcrumbs until completely covered.
Add sunflower oil to a deep pot over medium heat.
Once oil is hot, add in batches the arancini balls (around 4 at a time) and fry for 6 - 8 minutes turning so all sides are fried.
When cooked transfer to a plate covered in kitchen towels to absorb the excess oil.
Or allow to cool and keep in the fridge for up to 2 - 3 days and reheat in the oven for 20 - 30 minutes at 200*C / 400*F