Line a baking sheet with aluminum foil. Spray with non-stick cooking spray. Preheat oven to 450 degrees F.
Slice onion into thick rings. Discard the smaller center rings.
Pour the buttermilk into a large bowl. Add the onions to the buttermilk and let them soak, at room temperature, for at least 30 minutes.
Mix the flour, pepper, cayenne pepper and salt in a shallow dish. One by one, remove the onion rings from teh buttermilk and dredge in the flour. Tap off the excess and place on a dish. Continue with remaining onions.
Pour the breadcrumbs into another shallow dish. Moving quickly, take the onion rings that are now dredged in flour and, one at a time, dip them into the buttermilk again and then into the breadcrumbs. Make sure they are fully coated and then place on the baking sheet. Continue with remaining onions.
Bake onions for 15 minutes, flipping halfway through cooking time. If you like crispier rings, lightly spray the rings with canola oil so they crisp up while baking. Enjoy!
by The Savvy Kitchen