To make a great onion ring, you need large yellow onions, and definitely not the supersweet kind. Slice the onions into half-inch slabs and separate the slabs into rings. Place the rings in buttermilk to wet them and shake off the excess. Toss them in seasoned flour. Then into fairly thin beer batter (beer, flour, salt, touch of baking powder). Shake off the excess and into the fryer.