Grate peeled potatoes on the medium size hols of the vegetable grater. Place in a large strainer and let it soak off, pressing the potatoes down to remove as much water as possible. You can also use cheesecloth for that.
Use the same side of the grater for the onion. Drain most of the liquid as well. Transfer to a large bowl, add potatoes, crushed garlic cloves and egg. Mix and soak off any extra water.
Add flour and season generously with salt and pepper. Mix and add more flour if you feel like the mixture is too moist.
Heat up 5 tbsp of oil in a frying pan over medium heat. Place medium size flat circles on to the oil (you can use a spoon for that) and fry until golden brown on both sides. Once cooked place on a plate laid out with kitchen roll for any excess oil to soak off.
Serve and enjoy while hot with a big spoon of sour cream on top.