There are all sorts of tricks for making deep-fry batters both delicate and crisp. Sometimes, recipes call for beating in beer or club soda (the little air bubbles lighten the mixture), or adding vodka (alcohol boils off more quickly than water, enhancing a batter's texture). For these onion rings, Richard Blais uses both strategies and amplifies their effect by aerating the batter in a siphon. The results are some of the laciest, crunchiest onion rings you'll ever taste. This batter is equally good on all kinds of fried foods, like chicken, pork cutlets, fish and other vegetables.