Place slices of onion in a shallow dish. Pour the buttermilk over the top and let them soak for 1 - 2 hours while refrigerated.
Preheat oven to 450°.
Line baking sheet with parchment paper or foil.
Combine bread crumbs and corn flakes and place half of the crumbs in a large dish, add the Sour Cream & Onion Gourmet Fries Seasonings. Reserve the rest for when the first batch is used up. This should help avoid clumping and they should stick better to the onions.
Dip each soaked onion ring into the crumb mixture; coat well.
Place rings onto two cookie sheets. Lightly spray with oil.
Bake for approximately 12 minutes or until golden brown.
Lightly sprinkle additional Sour Cream & Onion seasonings.