- To make the dough, mix the flour together with the egg, olive oil, water (start with 120ml and add more if needed) and a good pinch of salt. Bring together into a dough. Tip onto a clean surface and knead for 1 minutes to fully bind everything and then rest for 30 minutes.
- For the filling, boil the potatoes for 8-10 or until tender in a large pan of boiling water. Drain and mash.
- Melt the butter in a large non-stick frying pan over a medium heat. Add the onion and a good pinch of salt and pepper. Mix well and cook, stirring occasionally, for 10-12 minutes until caramelised. Add to the potatoes and season well. Mix together and leave to cool.
- Divide the dough into two and roll one piece out until its about 1/3 cm thick. Dust both sides well with flour. Using an 8 ½cm diameter glass, cut out rounds to make the dumplings. You should get about 15 from each piece of dough. Pop a teaspoon of filling onto each round and brush the edge with a tiny bit of water. Fold the dumplings in half and seal well. Repeat with the rest.
- Boil the dumplings for 4-5 minutes in a large pan of simmering water until they are all floating. Remove with a slotted spoon. Serve the vareniki with loads of melted butter, dill, sour cream and salt and pepper.
For the dough
300g plain flour, plus extra for dusting
2 tbsp olive oil
For the filling
1 onion, finely chopped
350kg potatoes, peeled and 2-3cm cubes
Salt and pepper