01
Step 1
Pour enough oil into a Dutch oven so it comes about halfway up the sides, then heat it over medium until it reaches around 375°F (190°C). While the oil warms up, mix together the buttermilk, flour, egg, baking powder, paprika, celery salt, parsley, hot sauce, salt, and pepper in a large bowl. Whisk everything until the batter is nice and smooth.
02
Step 2
Carefully separate the onion slices into individual rings, then dip each one into the batter, letting any extra drip off. Gently place the rings into the hot oil in batches—don’t overcrowd the pot. Fry them until they’re a deep golden brown, about a minute on each side. Once cooked, transfer the onion rings to a plate lined with paper towels to soak up any excess oil. Keep going until all the rings are fried, then serve them up right away while they’re still crispy.