Combine the buttermilk and hot sauce in a bowl with 2 teaspoons of Essence. Add the onion rings and toss to coat. Marinate in the refrigerator for at least 1 hour, covered.
Heat the oil in a large pot to 360°F.
In a shallow bowl, combine the flour with 2 tablespoons of the Essence. Dredge the onions in the seasoned flour, coating each ring evenly. Shake off any excess flour and carefully place the rings in the hot oil. Fry until golden brown, turning to cook evenly and prevent sticking, about 3 minutes per batch. Remove from the oil and drain on paper towels. Season the fried onion rings with Essence, and repeat with the remaining ingredients.