Belarusian
Peel the potatoes and onion and grate them on the fine side of a box grater into a bowl.
Squeeze the mixture firmly in a clean kitchen towel over a bowl. Let the liquid stand for 5 minutes, pour off the water and return the settled starch to the potatoes.
Stir in the egg, flour, salt and pepper until evenly combined.
Heat a 3-4 mm layer of oil in a large frying pan over medium-high heat.
Drop heaped tablespoons of the mixture into the oil and flatten them to about 1 cm thick.
Fry for 3-4 minutes per side until deep golden and crisp, adding more oil between batches as needed.
Drain on paper towels and serve hot.