Store any leftover dredging mixture (from Step 3) in an airtight container in refrigerator up to 2 weeks. Make sure your oil is hot enough, and that it comes back up to temp, before adding the second batch of onions.
2 large sweet onions, cut into 3/8-inch-thick slices
3 cups buttermilk
2 cups all-purpose flour
1 cup plain yellow cornmeal
2 teaspoons table salt
1/2 teaspoon ground red pepper
How to Make It
Separate onion slices into rings, and place in a 9-inch square baking dish. Pour buttermilk over onion rings. Cover and chill 2 to 24 hours.
Pour oil to depth of 2 inches into a Dutch oven; heat to 360°.
Stir together flour and next 3 ingredients in a shallow dish. Dredge onion rings in flour mixture, and place on a baking sheet. Discard buttermilk.
Fry onion rings, in batches, 2 minutes or until golden brown, turning once. Drain on paper towels.
Serve onion rings immediately, or keep warm in a 200° oven until ready to serve.