Vareniki with Cherry and Sour Cream (Russian Cherry Dumplings)

In a large bowl, whisk together the flour and salt. Make a well in the center and add the warm water and egg. Use a fork to gradually incorporate the flour into the liquid until a shaggy dough forms. Turn the dough out onto a lightly floured work surface and knead for 5-7 minutes, until smooth and elastic. Cover the dough with a kitchen towel and let it rest for 30 minutes.

While the dough rests, pit the cherries and halve them. Toss the cherries with the sugar in a bowl and let them macerate, stirring occasionally, until the sugar dissolves and a syrup forms, about 15 minutes. Drain the cherries, reserving the syrup for serving if desired.

Roll the rested dough into a thin sheet, about 1-2 mm thick, on a lightly floured surface. Use a round cookie cutter (about 8 cm in diameter) to cut out rounds. Gather the scraps, re-roll, and cut more rounds until all dough is used.

Place a spoonful of the drained cherries (about 1 tablespoon) in the center of each dough round. Fold the dough over to create a half-moon, and press the edges together firmly, using a fork or your fingers to crimp. Make sure the edges are well sealed to prevent the fruit from leaking during boiling.

Bring a large pot of salted water to a rolling boil. Drop in the vareniki in batches, being careful not to overcrowd. Cook for 3-4 minutes after they float to the surface, until the dough is tender and the filling is hot. Remove with a slotted spoon.

Serve the vareniki warm, topped generously with sour cream. If you like, sprinkle with a little sugar and a drizzle of the reserved cherry syrup.