Classic rings of fried onion goodness.
Add the oil to the deep fryer and heat it up to 365 F.
Roll the onion slices into rings. In a bowl, stir the flour, baking powder and salt together.
Dip the onion slices into the flour mix to get an even coating. Whisk the egg and milk into the flour mixture with a fork. Dip the floured rings into the batter to coat, then leave them on a wire rack until they stop dripping. While you wait, spread the bread crumbs out on a plate. When the rings stop drifting, place them one at a time into the crumbs, and use your fingers to scoop the crumbs up over them to get a full coat. As you take the rings out of the crumbs, give them a firm tap to shake off any excess. The remaining coat should be plentiful and stuck firmly.
Fry the rings a few at a time for 2 to 3 minutes, or until golden brown. Drain the rings on paper towels, season with seasoning salt, and serve.