For the rice, in a large pot, bring the water (or stock), lemon and saffron to a boil. Add the rice, stir, cover the pot and reduce the heat to medium-low. Cook the rice, stirring occasionally, until the liquid is fully absorbed and the rice is tender, 18 to 20 minutes (the rice will be very sticky). Spread the rice out in a large dish to cool for 30 minutes.

Once the rice is mostly cooled, stir in the mozzarella and Parmesan and season to taste. Cover and chill the rice completely (this can be made a day ahead).

To assemble the arancini, line a baking tray with parchment paper. Use a scoop or ¼ cup (60 mL) measure to portion the rice onto the lined tray. Cut the ’nduja into as many pieces as there are rice portions.

Fill a bowl with cool water to periodically wet your hands to keep the rice from sticking to them. Shape each rice portion into a flat patty and set an ’nduja portion into the centre. Press the rice around the ’nduja to hide it in the centre, shape it into a ball and return to the tray. Repeat with the remaining rice portions.

In a small bowl, whisk the flour and water until smooth. Place the breadcrumbs in a second bowl. Dip an arancino partially into the flour paste and rub the paste to fully cover it (just a sheer layer is needed to get the breadcrumbs to stick). Roll the arancino into the breadcrumbs to cover completely, then return it to the baking tray. Continue with the remaining arancini. Chill until ready to cook, or freeze on the tray and then transfer to a sealed container, thawing in the fridge before baking.

Set your air fryer to 375°F (190°C) and bake as many arancini as will reasonably fit on the tray, leaving ½ inch (1.2 cm) between them. Bake for 20 minutes, until golden brown and crisp. Serve hot on their own or with tomato sauce.