Supplì al telefono — crispy rice croquettes with mozzarella

Chop the onion very finely and finely grate the Parmesan. Heat the broth in a separate saucepan and keep it hot. Do not rinse the rice: its starch will help bind the mixture. Have ready two wide, shallow metal trays that will fit in the refrigerator.

Heat the olive oil in a wide saucepan and cook the onion over low heat for about 5 minutes, until translucent. Add the rice and stir for about 2 minutes. Add the passata and 200 ml hot broth. Cook uncovered over low heat, stirring frequently, for about 18–20 minutes from the time the broth is added. Add the remaining broth in small amounts only when the previous addition has been absorbed and the rice is still too firm; you do not need to use all 600 ml. At the end, the grains should be al dente and the mixture thick and cohesive, with no loose liquid in the bottom. If the rice is cooked but the mixture is too loose, stir for a little longer without adding liquid. Take off the heat, add all the Parmesan, 3 g salt and all the pepper, and mix.

Immediately spread the rice on the two metal trays in a layer no thicker than 1 cm. Let stand for only about 10 minutes, until the strongest steaming subsides, then place in the refrigerator. Do not wait for it to cool completely on the counter; the rice should be in the refrigerator no later than 1 hour after cooking. Refrigerate for about 50–60 minutes, until cold and distinctly firm. Cover the trays once the steaming stops. While the rice chills, prepare the mozzarella and breading station as described in the following steps.

While the rice chills, drain the mozzarella in a strainer in the refrigerator, pat dry with paper towels and weigh out 160 g. Cut into 16 short sticks. Once the rice is cold, divide all the mixture into 16 similar portions. Flatten each in your palm, place one mozzarella stick in the center and enclose it completely in rice. Shape into an oblong croquette about 7 cm long and 3–4 cm thick. Press the seam and ends especially firmly: the cheese must not stick out or show through cracks. Place the shaped croquettes on a tray in the refrigerator.

Prepare three dishes: one with flour, one with whole eggs thoroughly beaten with the remaining 1 g salt, and one with breadcrumbs. Coat each croquette lightly in flour and shake off the excess, dip in egg, then coat thoroughly in breadcrumbs. Repeat the egg dip and breadcrumb coating; do not add a second flour coating. Gently press the breading onto all sides, especially the ends. Discard any flour, egg and breadcrumbs left in the dishes. Keep the breaded supplì refrigerated and take out only the batch you are about to fry.

In a pot about 18 cm across with a capacity of 3–4 l, heat the frying oil to about 170°C; do not fill the pot more than halfway with oil. A breadcrumb should sizzle immediately, but the oil must not smoke. Carefully add 4 croquettes at a time and fry for about 6–8 minutes per batch, turning gently. Maintain a similar temperature between batches. The coating should be evenly golden, and the rice steaming hot throughout the center; the mozzarella should be completely melted. You can break open one croquette from the first batch to check the center. If it is still cool, fry the remaining croquettes longer; a golden coating alone is not enough.

Lift out the croquettes with a slotted spoon and drain briefly on paper towels. Serve right away, 4 per serving, while the mozzarella inside is melted and stretchy. The remaining frying oil is not part of the dish. Do not reheat this batch of rice again: after its first cooking, it has already been chilled and reheated during frying.