Combine 1 cup of all-purpose flour, 1/4 teaspoon of baking powder and salt. Set aside.
Whisk 1 egg and then whisk in 1 cup of buttermilk.
Slice 4 large Granny Smith apples into 1/4 inch thick slices using varying sized biscuit cutters to make “rings” out of the slices, discarding smallest circle containing core.
Heat oil to 375 degrees F. (Caution: Do not let the oil get too hot or your rings will burn quickly. If rings are cooking too quickly, lower the heat of the oil a bit.) Combine the liquid and dry ingredients while the oil heats up.
Dip apple rings into batter, removing any excess. A little is okay, it gives them a nice swirly look. Cook in oil in small batches, turning frequently to monitor browning.
When the rings are golden brown, remove to a wire rack and sprinkle with sea salt.