Peel the white onions and slice them into thick rings, about ½ inch wide. Carefully separate the rings and remove the centers to create hollow spaces for stuffing.

Take a generous pinch of shredded mozzarella cheese and press it firmly into the hollow center of each onion ring. Avoid overstuffing to prevent the cheese from leaking out during frying.

Prepare three shallow bowls for coating: Place flour in the first bowl, beaten eggs in the second, and a mixture of breadcrumbs and grated Parmesan cheese in the third.

Coat each stuffed onion ring by dredging it in flour, shaking off excess. Dip it into the beaten eggs, ensuring full coverage, then roll it in the breadcrumb mixture, pressing gently to adhere. For extra crispiness, repeat the egg and breadcrumb steps for a double coating.

Heat cooking oil in a deep skillet or frying pan over medium heat until it reaches 350°F (175°C). Fry the onion rings in batches, being careful not to overcrowd the pan. Cook for 2–3 minutes per side, or until golden brown and crispy.

Transfer the fried onion rings to a paper towel-lined plate to drain excess oil.

While the onion rings are frying, prepare the garlic butter. In a small saucepan, melt the butter over low heat. Add the minced garlic and sauté for 1–2 minutes, just until fragrant. Be careful not to burn the garlic.

Drizzle the garlic butter generously over the fried onion rings or serve it on the side as a dipping sauce. Garnish with fresh parsley if desired and serve immediately.