Peel potatoes. Grate them along with the onion on your grater. Put the mixture in to a paper towel and slightly squeeze. You don't have to let all the liquid go, but most of it.
Place potato-onion mixture in to the bowl. Add an egg and flour, about 1/3 tspn salt and some freshly ground pepper. Mix very well.
Cook just like you would cook a pancake- spoon the mixture on a heated oiled pan, fry on each side for about 3 minutes on a medium-high heat until gold in color.
Place cooked potato cakes on a paper towel to absorb that extra oil.
Serve with sour cream and chopped cilantro. Enjoy!