1. Peel and finely grate the potatoes and onion. 2. Squeeze out excess liquid from the grated potatoes into an empty bowl. Place squeezed potatoes in a large bowl. Check the bowl with potato juice. Once the water settles, you should find starch has settled at the bottom of the bowl. Carefully drain liquid and return starch to shredded potatoes. 3. In a bowl, mix the grated potatoes with the egg, flour, salt, and pepper. 4. Heat oil in a pan, then spoon small portions of the mixture into the hot oil, flattening them into pancakes. 5. Fry until golden brown on both sides. 6. Serve hot with sour cream.