Preheat a large shallow pot full of about 2 inches of oil over medium heat.
In a medium sized bowl mix together your flour, baking powder, salt, cinnamon and sugar.
Combine your buttermilk and egg in a small bowl.
In a third bowl combine your cinnamon and sugar for the topping then dump onto a plate.
Dump your buttermilk and egg into the flour mixture and stir together.
Slice your apples into thin round slices, about 1/4 inch thick (I used my mandolin on thick). Cut out the cored of your apples and cut each apple slice into 2 rings using a round cookie or biscuit cutter.
Dip your apple slices into your batter and allow excess batter to drip off.
Put a few slices at a time into the preheated oil and allow to cook for a couple minutes, flipping after the bottom half is a golden brown color. Then cook on bottom side till browned too.
Remove from oil and place on some paper towels to drip excess oil off.
Dip apple slices into cinnamon sugar mixture, and coat on both sides.
Serve immediately as they're definitely best while hot. And bonus - they taste amazing alone, but also amazing dipped in chocolate!