Slice onion into thin rings.
Place in container with buttermilk; cover and refrigerate 1-2 hours.
In a medium mixing bowl, combine flour and seasonings.
Heat oil in a medium saucepan to 375 degrees.
Remove a handful of onions from buttermilk, dip in flour mixture (shake to remove excess) and place in hot oil .
Fry until golden brown; remove from oil and place on paper towel-lined plate.
Season with salt as desired.