If using a slicer, slice to create rings at first and once the onion becomes wider, focus on slicing the sides and creating strings. As onion gets to the other end, you can focus on creating rings again.
In a bowl, separate your strings and rings well and pour buttermilk over them. Mix well. I like to use my hands to make sure I get all of it.
Cover and refrigerate for about 4 hours.
When ready to fry, place 2 cups of flour on a plate. Add any seasonings or spices you want at this time and mix well.
Add onions a bit at a time making sure you get as much of the buttermilk shaken off as you can.
Dredge the onions in the flour making sure you coat well and move over to another plate. Continue on to the rest of the onions, adding more flour for dredging as you go along.
Heat oil over medium heat while you dredge the onions.
Once oil is hot, add one piece of onion string or ring to test if it is ready to fry. Once it is, add pieces a couple at a time. Make sure you don't stack them as we will fry in batches.
A couple of minutes into frying, move the onions around a bit. Make sure to watch my video.
Continue to flip and move around pan while they fru to ensure even cooking and color.
When the first batch is done, remove to a paper towel lined serving dish. Continue to fry the rest.
To keep your batches warm, set your oven to "warm" and keep the ready batches there while you fry the rest. If your oven doesn't have a "warm" setting, set it at 180ᴼ degrees and you are good to go!
Simple Spicy Mayo Mustard Sauce for dipping
Mix mayonnaise, mustard and hot sauce and you are all done!