Cut into ½" rings and separate into individual rings.
Set out 3 shallow bowls.
In the first bowl combine the flour, seasoned salt and pepper.
In the second bowl, whisk together the eggs with the milk.
In the third bowl, place the panko breadcrumbs.
Place the onion rings into the flour mixture.
Turn to get the flour on all areas.
Place on a wire rack and let rest for 5 minutes.
Return the rings to the flour and again turn to coat.
Shake off any excess and (working in batches as needed), place the rings into the egg mixture.
Dunk the rings, making sure they get coated evenly. I like to handle the rings from the inside so that my fingers do not knock any of the coating off the outsides.
Shake off any excess coating and transfer to the panko breadcrumbs.
Turn the rings to coat well in the breadcrumbs then transfer to a wire rack to let rest for 5 minutes.
While the rings are resting heat 2-3" of oil to 350 F in a Dutch oven or deep fryer.
Working in batches if needed, fry the rings for 2 minutes, then flip and continue cooking until golden brown.