Peel and coarsely shred the potato and onion using a grater or mandoline. Squeeze out as much liquid as possible using a cheesecloth or colander. Let rest for 2 minutes, then squeeze again.

In a large bowl, whisk together the flour, egg, salt, and pepper. Stir in the potato-onion mixture until evenly coated.

Heat 2 tablespoons of vegetable oil in a medium skillet over medium-high heat until shimmering.

Drop spoonfuls of the mixture into the skillet, flattening gently with a spoon. Cook for about 1½ minutes or until the edges are golden. Flip and cook for another minute until crisp and golden.

Transfer cooked latkes to a paper towel-lined plate. Repeat with remaining mixture, adding more oil as needed.

To keep latkes warm and crisp, place them in a 200°F oven until ready to serve.