Amazing Crispy Fried Onion Rings - cooking recipe

Ingredients

3 large yellow onions
3/4 cup all-purpose flour
1/4 cup cornmeal (or corn muffin mix, as a substitute)
1/2 teaspoon baking powder
1 teaspoon salt
1/4 teaspoon baking soda
1/8 teaspoon cayenne pepper
1/3 cup milk (or more if desired or necessary)

Preparation

In a 3 quart pot, heat about 3-4 inches of vegetable oil on medium to medium high heat.
Combine all dry ingredients in a medium sized bowl and mix in milk with a whisk, adding more milk if needed until mixture is the consistency is like a thin-medium pancake batter.
Cut onions into thin rings and toss in batter.
Place a single ring into the oil to test for appropriate heat. Onion ring should sizzle and start to brown immediately.
Place small batches of onion rings into the oil and when they turn dark golden brown on one side, flip them over to the othe side with a slotted spoon or carving fork.
Drain on a paper towel-lined plate. Repeat until all onions are done. (Add a bit more milk to the batter if it appears that the last batch isn't getting coated enough.).
I like to salt the cooked onion rings, but that is optional.