Preheat the oven to low. Peel and grate the potatoes and finely chop the onion; put both in a strainer. Press with a spoon or the base of a saucer to squeeze out as much starchy liquid as possible.
Transfer the potato mixture to a bowl, add the egg, flour, salt and pepper and mix well.
Pour the oil into a frying pan to a depth of about 10 mm and heat until it shows a haze.
Put a tablespoon of the mixture into the oil, flattening to a small pancake about 5 cm in diameter. Keep adding more tablespoons of the mixture to the pan, cooking four to six at a time, until you have made 12 pancakes. Fry for about 1 minute or until golden on the bottom, then turn and cook the other side until crisp and golden but still soft in the centre.
Remove the pancakes from the pan, drain on paper towels and keep warm in the oven.
Cut the smoked salmon into small strips. Serve each pancake topped with a spoonful of sour cream and a few strips of salmon, and garnish with the sprigs of dill, onion slices or capers.
NUTRIENTS PER SERVING, WHEN SERVING 4:
good source of vitamins B group, C, E and folate, and selenium.