Ukrainian
Mix the flour with 0.5 tsp salt, add the egg, oil and water, and knead for 8-10 minutes into a smooth, firm dough. Cover and rest for 30 minutes.
For the filling, press the farmer cheese through a sieve or mash it well with a fork, then mix in the second egg, the sugar and 0.25 tsp salt.
Roll the dough out on a floured surface to 1-2 mm and cut out 7 cm circles with a glass; knead the scraps together and roll again.
Put 1 heaped tsp of filling on each circle, fold it in half and pinch the edges firmly to seal. You get about 60 vareniki.
Bring the water to a boil with 1 tsp salt and cook the vareniki in batches, stirring gently, for 4-5 minutes after they float.
Lift them out with a slotted spoon into a bowl and toss with the melted butter so they do not stick.
Serve hot with the sour cream.