Toast 2 cups of panko and set aside for your breading.
Soak 1/2 cup of untoasted panko bread crumbs in milk for a few minutes while you get the rest of your hamburg steak ingredients.
In a large bowl, mix ground beef, ground pork, onions, 2 eggs, and a pinch of salt and pepper. Add in soaked panko crumbs.
Mix with your hands until thoroughly combined, but try not to overmix. Form 16 patties.
Mix 1/4 cup flour and two eggs in a shallow dish.
Bread each hamburger patty by dipping into the flour/egg batter and then into the toasted panko.
Place breaded patties into the air fryer and spray with oil spray (you may have to do this in two batches).
Air fry at 400 degrees for 10-12 minutes, or until patties are cooked through.