Spinach-Feta Pierogi with Mint-Dill Yogurt

Steps

1. Make the dough first: in a bowl, mix the flour with half of the salt. Add the egg, sour cream and water and stir into a shaggy dough.
2. Knead the dough on a lightly floured counter for 5 minutes until smooth, then cover and rest it for 30 minutes while you make the filling.
3. Heat the olive oil in a large skillet over medium heat. Cook the onion for 5 minutes until soft, add the garlic for 30 seconds, then add the spinach in batches and cook until wilted, about 4 minutes.
4. Tip the spinach mixture into a sieve, cool 10 minutes, then press out as much liquid as possible and chop it finely. Wipe the skillet dry for later.
5. In a bowl, combine the chopped spinach mixture with the ricotta, feta, black pepper, nutmeg and the remaining half of the salt.
6. Make the herb yogurt: stir the Greek yogurt with the mint, dill and lemon juice, then chill until serving.
7. Roll the rested dough to about 1/16 inch thick and cut into 3-inch rounds, rerolling scraps once, for about 28 rounds.
8. Place a heaping teaspoon of filling on each round, fold into a half-moon and pinch the edges firmly to seal.
9. Bring a large pot of water to a boil. Cook the pierogi in batches until they float, then 2 minutes more, about 4 minutes total; lift out with a slotted spoon.
10. Melt the butter in the skillet over medium heat and fry the boiled pierogi in batches until golden on both sides, 2 to 3 minutes per side, so the filling is steaming hot.
11. Serve the pierogi hot with the herb yogurt on the side.