Preheat oven to 400 degrees.
Cut out some onion rings for the outside lining. Dice the rest.
Combine all the ingredients and stuff the onion rings so they are flat.
Chill the patties for 15 minutes
Prepare breading station by mixing the breading and stirring the egg wash.
Take the patties through the stations: flour, egg wash, breading.
Bake for 15-20 minutes