2 large Vidalia onions or other sweet onions
1 quart(s) peanut oil
2 cup(s) buttermilk
Kosher salt and freshly ground black pepper
4 cup(s) all-purpose flour
1/2 teaspoon(s) cayenne powder
Peel the onions and slice them crosswise into 1-inch-thick slices. Separate each slice into individual rings, then remove the papery thin membrane covering the inside of each ring.
Heat the oil in a large, heavy-bottomed medium stockpot over medium heat, or in a tabletop deep fryer, to 375 degrees F. Line a baking sheet with paper towels and set aside.
While the oil is heating, put the buttermilk in a large baking dish and season liberally with salt and pepper. Divide the flour between 2 large baking dishes and season each dish liberally with salt and pepper and 1/4 teaspoon of the cayenne.
Working in batches, dredge some of the onion rings in one of the dishes of flour and tap off the excess. Dip the rings in the buttermilk, allow excess to drain off, and then dredge the rings in the second dish of flour, making sure to coat the rings evenly. Tap off excess and transfer the batch of coated rings to the hot oil. Fry the rings, turning once or twice, until golden brown and tender, about 4 minutes. Remove with a mesh skimmer and drain on the baking sheet lined with paper towels. Season immediately with salt. Repeat until all of the rings have been cooked. Serve hot.
Shoestring Onion Rings: If you're not into big onion rings, make crisp, crunchy, thin onion rings. Peel 2 large Vidalia onions and cut crosswise into 1/4-inch-thick slices. Separate each slice into individual rings and then remove as many of the papery thin membranes covering the inside of each ring as you can. Proceed as for the recipe above.
Recipe shared from: http://www.delish.com/recipefinder/buttermilk-onion-rings-recipe?click=recipe_sr