Gather all ingredients. Preheat the oven to low, about 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 oil in the bottom of a heavy skillet over medium-high heat. Drop two or three 1/4-cup mounds of batter into hot oil, and flatten with the back of a spatula to make 1/2-inch-thick pancakes.

Fry, turning pancakes once, until golden brown. Transfer pancakes to a plate lined with a paper towel to drain. Keep warm in the oven until serving. Repeat until all potato mixture is used.