Boil potatoes in their skin until tender. Let cool. (Ideally, refrigerate overnight.) When cool, peel potatoes and grate them.
Add flour and salt and mix thoroughly. You should end up with floury crumbles.
Place the oil (or other fat) in a large frying pan over medium low heat. Gently fry and flip until the crumbles are nicely browned but not burned. Remove from the pan and serve with a dollop of sour cream on top. Tastes great with refreshing apple sauce.