Gather all ingredients. Preheat the oven to 200 degrees F (95 degrees C).

Finely grate potatoes and onion into a large bowl. Drain off any excess liquid.

Mix in egg, salt, and pepper. Add enough flour to make the mixture thick, about 2 to 4 tablespoons all together.

Heat 1/4 inch of oil in the bottom of a heavy skillet over medium-high heat. Drop 1/4-cup mounds of batter, two or three at a time, into hot oil and flatten with back of a spatula to make 1/2-inch-thick pancakes.

Fry, turning pancakes once, until golden brown and crisp. Transfer to a paper towel–lined plate to drain. Keep warm in the preheated oven until ready to serve. Repeat until all potato mixture is used.

Serve warm.