01 -
Peel onions and cut into 1-centimetre rings. Separate rings gently. Slice mozzarella cheese into 4 even strips. Place a smaller onion ring inside a larger one and fill the gap with mozzarella strips, adding an extra layer of cheese if desired. Repeat with all remaining onion rings. Arrange assembled rings on a tray and freeze for 1 hour to firm.
02 -
Prepare three bowls: one with flour, one with beaten eggs, and one with breadcrumbs. Remove frozen onion rings from freezer.
03 -
Coat each stuffed onion ring first in flour, then dip in beaten egg, then coat with breadcrumbs. For a crispier crust, dip again into egg and breadcrumbs. Return breaded rings to the freezer until ready to fry.
04 -
Heat oil in a deep pot to 175°C. Fry the breaded onion rings in batches, turning occasionally, until golden brown. Do not over-fry to prevent cheese from leaking. Remove rings with a slotted spoon and drain on paper towels.
05 -
Serve onion rings hot with marinara sauce for dipping.