Slice the onions into rings about ⅜-inch (0.5 cm) thick.
2 large sweet onions
Separate the rings and toss them with the ½ cup flour.
½ cup Cathy's Gluten-Free All-Purpose Flour Blend
Heat at least an inch (2.5 cm) of oil to 375℉ (190℃).
lard or tallow
Meanwhile, in another bowl, beat the egg with avocado oil and milk.
1 large egg, ¼ cup avocado oil, 1¼ cups whole milk
Add the remaining 1¼ cups of flour, baking powder, and salt. Beat the batter until it's smooth.
1¼ cup Cathy's Gluten-Free All-Purpose Flour Blend, 1 teaspoon gluten-free baking powder, ½ teaspoon fine sea salt
Dip each floured onion ring into the batter and then carefully place it into the hot oil. Fry it until it's golden on one side. Turn each one over and fry on the other side until it's golden, too. Watch them closely; this won't take long.As they finish, remove each battered onion ring to a paper towel-lined plate. Don't fry too many at once. If the oil becomes crowded, the onion rings will stick together, and the temperature of the oil will drop.
Video
Notes
The temperature of the oil is important. If it's too hot, the onion rings will burn on the outside before they get cooked through on the inside. If it's not hot enough, the onion rings will absorb too much and be oily and soggy by the time they are cooked through.