1 large egg, lightly whisked
2 tablespoons sour cream
1 cup whole milk
1 cup water
5 cups all-purpose flour, plus more for surface and dusting
Yellow cornmeal, for dusting
Italian Plum Filling:
24 small Italian plums
2 tablespoons sugar
Spiced Sour Cream:
1 cup sour cream
3 tablespoons confectioners' sugar
1/2 teaspoon pure vanilla extract
1/4 teaspoon freshly grated nutmeg
Make the dough: Whisk together egg and sour cream. Whisk in milk and water. Stir in flour, 1 cup at a time.
Turn out dough onto a floured surface. (Dough will be loose and sticky.) Using a bench scraper, turn and fold dough to knead, dusting with flour as needed, until elastic and no longer sticky, 8 to 10 minutes. (Dough will come together as you knead it. Be careful not to add too much flour, since it will toughen the dough.) Cover with an inverted bowl; let rest for 1 hour.
Divide dough into 4 equal pieces. Line a rimmed baking sheet with a clean linen towel, and dust generously with cornmeal to prevent sticking.
Roll out 1 piece of dough on a lightly floured surface into a 1/8-inch-thick round (keep other pieces covered).
Cut out circles very close together, using a 3-inch cutter or glass (5 inches for the plum version). Cover with plastic wrap to prevent dough from drying. Repeat with remaining dough.
Cut a slit into (but not through) each plum; remove pits. Fill cavity of each plum with 1/4 teaspoon sugar. Close plum before wrapping in dough. Use 1 plum for each pierogi.
Mix together sour cream, confectioners' sugar, vanilla extract, and nutmeg. Serve chilled.
Bring a large pot of water to a boil.
Place one plum in center of each dough circle. Holding 1 circle in your hand, fold dough over filling. Pinch edges, forming a well-sealed crescent.
Transfer to cornmeal-dusted towel, and loosely cover with plastic wrap. Repeat with remaining dough circles and filling.
Working in batches, transfer pierogi to boiling water. They will sink to the bottom and then rise. Once they have risen, cook through, about 2 minutes more (or up to 4 minutes for plum pierogi, depending on ripeness).
Transfer to a platter using a slotted spoon, and dot with sour cream.
| Adapted from Martha Stewart