Put potatoes and onions into a colander and squeeze out as much moisture as possible.
Mix in egg and flour then season with salt and pepper.
Heat 1/4" of oil over medium. The oil is ready when a potato sputters when dropped into it. Fry latkes by adding a spoonful of the potato mixture to the oil and flattening it with a spatula. Cook for several minutes on each side until golden brown. (If the latkes are falling apart add a little more egg and flour)