Take large yellow onions and slice them thin.
select only the rings that are approx 2 inches across or larger for use.
Using your fingers pull each ring apart so it is a strip.
Put the onions in a plastic (lexan etc) ventilated/covered tub and put in refrigeration to breathe for 24 hours.
When you have an order to serve, take a handful of the onion strips and put them in an egg bath (eggs beaten with a little milk) - coat well - then strain them in a strainer, chinois etc.
Coat them with regular AP flour - and shake them off well to get all the excess flour off ... then, put them into the fryer basket (a "half basket" as noted above) and nestle a second half-basket on top of the first to compress the onions and hold them together.
Drop this "doubled basket" into the fryer - 360 degrees and watch carefully - they burn quick.
When you take them out, pull the baskets apart and there you have it, an onion brick. Sprinkle with a little salt.