Potato Rosti Cakes

Peel and finely grate the onion. Peel, wash and grate the potatoes and add to the onion. Squeeze out and pour off the liquid. Carefully mix the egg and flour with the grated potatoes. Season well with salt and pepper. Heat plenty of oil in a skillet and put 2 tablespoons of the mixture into the skillet for each pancake. Press flat and fry on both sides until golden brown. Keep warm in the oven until all the pancakes are ready. Drain briefly on paper towel and serve hot.