These are hands down my favorite onion rings. They have the perfect smoky, seasoned buttermilk flavor and the onion breaks off perfectly when you bite into it. I started by marinating one yellow onion that I had cut into rings in buttermilk (enough to somewhat submerge the rings) and 2 teaspoons of my Emiril Schmemeril Seasoning.
The onion rings need to be marinated and refrigerated for at least one hour. I usually let mine sit in tupperware for 2-3 hours and periodically shake them. To coat my onion rings before frying, I combine equal parts flour, regular breadcrumbs, and panko breadcrumbs. I really like the difference in size between the flour and different breadcrumbs. The combination builds a nice crust and ensures the onion rings will be crunchy.
Also, I like to double dip the onion rings. In other words, take the onion from the buttermilk mixture and to the flour/breadcrumb mixture to get completely coated. Next, dip the ring back into the buttermilk and coat with the flour/breadcrumb mixture for the second time. Finally drop your onion rings into a fryer that has been heated to 350 degrees and cook until they are golden brown. Do not cook too many onion rings at one time; make sure they have enough room to kind of swim around and become the wonderful, tasty, friendly onion rings I know they can become.