I rarely fry anything. It makes too much of a mess. But once in a while, I get in the mood!
I don't have a deep fryer. I use a regular 3-quart pot and fill it about halfway up, then I use a thermometer to make sure I'm at the deep-fry temperature. Having your oil at the correct temp and making sure you have enough in the pot is key to successful frying.
So here is the recipe:
Onion cut into rings (Sweet onions like vidalias or mayans are best)
Complete Pancake Mix
any spice you like--I use just a bit of onion powder.
Mix the onion powder (or whatever) in with the pancake mix. Add seltzer until you have a nice consistency--not too thin, not too thick. Just a little thinner than actual pancake batter.
Dip the onions, then fry them a few at a time. Never overload your oil! You want to keep it at a steady temp, and too many goodies will bring it down. That will result in mushy onion rings. They cook up fast enough, so don't worry if you only do 2 or 3 at a time.
Drain on paper towels and add salt, as you go along.
Keep an eye on the temp, and either let the oil sit a minute to gain or remove from the burner for a few moments to let it cool again.
When you are all done, enjoy! But put a few in the freezer for the future. I flash-froze about 8 of them and put them in a bag. Today, I took them out and reheated them at 350 degrees in the toaster oven. They were great!
BTW, seltzer makes them 'puff' a little, so they come out just like diner onion rings.
PS...I strain and decant my oil into a canning jar and use it again. Twice is about my limit, but I think you can use it a few times with success.