01 -
Pair together one larger and one slightly smaller onion ring, nesting the smaller inside. Fill the space between them with mozzarella and insert a toothpick to secure each assembled ring.
02 -
In a shallow bowl, whisk together the flour, baking powder, and salt. Roll each assembled onion ring in the dry mixture to coat evenly. Place rings on a wire rack.
03 -
In a separate bowl, beat eggs, then whisk in milk. Add the wet mixture to the remaining flour dredge, stirring until a smooth, thick batter forms.
04 -
Dip each flour-coated onion ring into the batter, allowing excess to drip off. Press into Panko breadcrumbs until completely coated. Return to the wire rack.
05 -
Heat oil in a deep heavy-bottomed pot to 350°F (177°C). Fry the prepared rings in batches, turning halfway through, until both sides are deeply golden brown, approximately 2–3 minutes per batch. Drain on a paper towel-lined plate.
06 -
Carefully remove toothpicks, then serve immediately while hot with warm marinara sauce or your favorite dip.