I found this on tasty heres the link:
https://tasty.co/recipe/mozzarella-stick-onion-rings
Ingredients
for 8 onion rings
2 large white onions
8 slices mozzarella cheese
2 cups flour5 eggs
2 cups breadcrumboil, for fryingmarinara sauce
Preparation
Peel and cut onions into 1-centimeter (½ inch) rings. Separate the rings.Slice the mozzarella into 4 even strips.Place a smaller onion ring in the center of a larger one.Fill the gap between the rings with the mozzarella strips. For extra cheesiness, use two layers of cheese. Repeat with remaining onion rings and freeze for 1 hour.Place the flour, eggs, and breadcrumbs into three separate bowls.Coat each prepared ring in the flour first. Then dip into the egg, then the breadcrumbs, then the egg again, and one last time into the breadcrumbs. Repeat with the remaining onion rings and place in freezer.Heat the oil in a pot over high heat.Fry the rings until golden brown, being careful not to fry them for too long as the cheese may ooze out completely.Drain on a paper towel, then serve with marinara!Enjoy!