Squeeze the grated batatas well in a cloth and mix with the onion. Whisk the eggs with the flour, cumin, salt and pepper as well as the coriander greens and season to taste. Mix with the potatoes. Heat the oil in a heavy pan and add the potato mixture to the pan, tablespoon at a time. Flatten to cakes. There should be a total of 6 pieces. Brown for about 1 minute on each side.
Serve hot as an intermediate dish or as a side dish.
Cumin and coriander are very tasty. The amount added depends on personal taste.