While our pickled onion recipe calls for red onions, I used yellow onions, since they’re more ideal for onion rings (between the pickling and the breading, we’re imparting so much extra flavor that the sharper taste of a red would get lost anyway).
I sliced them into thick ½-inch rings and then went about the painstaking effort of removing the papery inner skin that separates the layers of the onion. I cannot emphasize to you how crucial this step is. Sure, it’s annoying now, but what's even more irritating is when you bite into an onion ring and the whole onion slides out of the breading along with it. Trust me, your patience will be rewarded.
Once the rings were prepared, I made the pickling liquor out of a combo of distilled white vinegar, sugar, and salt, heating it to a boil before pouring it over the ringed onions in a prep container and leaving them to pickle. While the recipe is for quick pickled onions, I left them to pickle in the fridge overnight to maximize that briny goodness.
The next day, I fished my now-pliable and delightfully sour pickled rings out of their brine and patted them dry on paper towels. They may be going straight into buttermilk, but you don’t want to bring too much excess vinegar to the party. Plus, you want to make sure that the dredge sticks to the ring instead of sliding off the vinegar.
Once they were fully dry, I set about battering and frying in the style of our Cook’s Country recipe: dipping the pickled onions in buttermilk; tossing them in a mixture of flour, cornstarch, Lawry’s Seasoned Salt, baking powder, salt, and pepper; and repeating the process. Double-dipping like this ensures a thick batter that’ll stick to the onion; plus, it has the added benefit of building up craggier edges for maximum crunch.