Start by removing the top and bottom of the onion, and remove the skin. Thinly slice the onion into strips and separate pieces.

In a medium-sized bowl, combine milk and vinegar, then stir. Let sit for 5 minutes, then whisk in egg.

In a shallow dish, mix together flour, salt, garlic powder and pepper.

Take onion slices and dip into flour mixture. This first coating of flour helps the batter adhere to the onion during the frying process. Once all onion slices have been coated in flour, dip the onion slices into the milk mixture, letting excess liquid fall off, then coat again with flour mixture, and set onto a plate or tray. Repeat process until all onion slices are coated.

Place onion slices into the freezer for 15-20 minutes, to set the coating. This will also help to keep the batter on the onion rings while they are being fried.

Once the onion rings are in the freezer, add 1" of oil to a deep skillet and warm over medium heat, to 350 degrees.

Remove onion slices from freezer, and fry in oil, in batches for 1-2 minutes a side, until golden brown. Remove and lay on paper towel-lined plate.