Peel the potatoes and zucchini and roughly grate them with a box grater.
Peel the onion and cut into fine pieces. Squeeze the grated zucchini and potatoes well and put them in a bowl with the onions.
Stir in egg, flour and spices and mix everything well.
Heat the oil in a pan and fry a small portion of the potato and zucchini mixture in the pan until golden brown on both sides.
Repeat the with the rest of the mixture.