From The Pioneer Woman Cooks
NOTE: Needs time in the fridge before starting!
1 large onion
2 cups buttermilk
2 cups flour
1 scant tablespoon salt
Lots of black pepper
1/4 to 1/2 teaspoon Cayenne Pepper
1. Slice onion very thin. Use a sharp knife or a vegetable slicer, probably set at 1/8" with the small julienne blade.
2. Place in a baking dish and cover with buttermilk for at least one hour.
3. Combine dry ingredients and set aside.
4. Heat oil to 375 degrees. Measure with a candy thermometer.
5. Grab a handful of onions, throw into the flour mixture, tap to shake off excess, and PLUNGE into hot oil.
6. Fry for a few minutes and remove as soon as golden brown. Place on paper towel to drain.
7. Repeat until onions are gone.