Grate the potatoes and other vegetables (if using).
Place the grated potatoes in a clean dish towel and squeeze out the excess water.
In a large mixing bowl, combine the vegetables, eggs, flour, onion (if using), and salt and pepper.
Drop by large spoonfuls onto a preheated, greased griddle or large frying pan. Flatten each pancake with the back of a spoon. Cook on both sides until browned.