eel the onions and slice them into ½-inch (1 centimeter) rings. Separate each ring.

Cut the mozzarella into 4 even strips per slice.

Take a smaller onion ring and place it inside a larger one. Fill the gap between them with mozzarella strips. For a cheesier option, use two layers of cheese. Repeat with the remaining rings and freeze them for 1 hour.

Prepare three bowls: one with flour, one with beaten eggs, and one with bread crumbs.

Coat each assembled ring in flour first. Dip it in the beaten eggs, then coat with bread crumbs. Repeat the egg dip and bread crumb coating once more. Continue with all rings and place them back in the freezer.

Heat oil in a large pot over medium-high heat until it reaches 350°F (175°C).

Fry the rings until they turn golden brown. Be cautious not to over-fry, as the cheese may leak out.

Drain the fried rings on a paper towel. Serve hot with marinara sauce.