In small bowl combine mayo, ketchup, 1/4 teaspoon black pepper, 1/8 teaspoon ground cayenne pepper, garlic and lime juice.
Set 1/4 cup of flour aside on a shallow plate. In medium bowl combine 1 cup flour, 1/4 teaspoon ground cayenne pepper, cumin, 1/2 teaspoon black pepper, garlic powder, beaten egg and 1 cup to 1 1/2 cups beer depending on how thick you want the batter.
Heat oil to 375 degrees. Dip onion rings in flour on shallow plate and then into batter. Fry battered onion rings in the hot oil until browned, about 4 minutes. Place on a paper towel covered wire rack while working in small batches.
Serve hot with Lime Mayo Sauce
NOTES
Non-alcoholic beer or club soda can be substituted for the beer.
Sweet onions are the best for flavor, but honestly, any onion makes a decent onion ring.
I personally like working with the batter when it is thin, so I use 1 1/2 cups of beer. You can start with 1 cup and add more as you work with it till you get it to the consistency that you desire.
Use an oil with a high smoke point, like peanut oil, vegetable oil, or canola oil.
Try to maintain a consistent fry temperature of 375 degrees. Use a candy or deep-fry thermometer. Dutch ovens are good heavy pans to fry in. Because of their thickness, they maintain and hold heat well.
Store leftover onion rings in an airtight container in the refrigerator. For best results, reheat them in the air fryer for 2-3 minutes.
