Peel onions and slice into 1/2 inch rounds. Separate into rings and place the rings into a large bowl or plastic bag. Add the milk to the onions and season with salt and pepper. Cover or seal and place in the fridge to marinate for at least 2 hours or as long as overnight, stirring a few times.
Mix all the dip ingredients in a small bowl and set aside in the fridge until ready to use.
Preheat oven to 400.
Put the bread mix in one large shallow bowl, the eggs in another, and the breadcrumbs in a third. Beat the eggs until smooth.
One by one, dip the breadcrumbs in the bread mixture, then the egg, and finally the breadcrumbs, shaking off excess coating after each dip. Place the finished onion rings onto a parchment lined baking sheet.
Once finished with coating all the rings, bake rings for 25 minutes until crispy on the outside and tender in the center.