To be honest, I am not an onion ring lover. In fact, I always order fries with my burgers. But onion strings are completely different. They're practically an addiction. No longer a casserole topper, I hope you enjoy them as much as I do!
Step 1: Supplies
Not a whole lot of supplies and ingredients are needed. The software you need are at least 1 onion (I used Vidalia), some milk, a fair amount of flour, salt and pepper, and oil for frying (I use Canola). For hardware you will need a knife (a super-sharp chef's knife work great), a pan for frying (I used an old cast-iron, but a Dutch oven should work too), and 2 shallow bowls/pie pans to hold the flour and milk. For easier cleanup, place newspapers around the stove. And, as always when frying, have a large cover in case of a grease fire.
Step 2: Mise En Place
Start by pouring about 1/4 to 1/2 inch of oil in your pan and start heating medium-high. We are aiming for a temperature between 320-350 degrees fahrenheit (using a candy or fry thermometer would be great but if you're like me and don't own one, just check often with an instant-read). While you wait for the oil to heat, peel the onions (try to leave the hairy, root end on so the onion doesn't fall apart when cutting). Slice as thinly as possible, rotating the onion for relatively even slices. Also, place the milk and flour in the pans/bowls (be sure to season the flour a bit with salt and pepper) and place them near the stove.
P.S. Mise en place is a cooking term for anything you do before you start cooking.
Step 3: Dredging and Frying
When the oil reaches desired temperature (320-350 F), start dredging the onions. To do this, first place some of the onion strings in the milk, just a brief dip. Next, dip the milk onions into the flour (my sister likes to double dredge but frankly, I find it makes them too breaded and onion-ringish). Carefully drop them into the oil, being wary of splatters and be sure to poke, stir, and move the onion strings around (I used a giant fork). Fry the onions until they are somewhat golden and drain on paper towels.
Step 4: Seasoning and Troubleshooting
Immediately after you remove the strings from the fryer, season with salt and a bit of pepper. Hold on to the edges of the towels and toss/shake to distribute the salt. The strings will be fairly sweet, so I prefer a little extra salt.
If your onion strings are pale and soggy then your oil is too cool.
If the oil is too hot, throw a bunch of onions in together. This will lower the temperature.
Step 5: Eating and Applications
These are great as a replacement for chips or popcorn but will also work to crunchify sandwiches and burgers. Traditionally, you put these on green beans but I find that to be a tragic waste. Just remember these can be extremely addictive!