01 - In a large bowl, mix flour and salt. Create a well in the center, add the egg and sour cream, and mix until a dough forms. Knead for about 5 minutes until smooth.
02 - Cover the dough with a clean towel and let it rest for 15 minutes.
03 - In another bowl, combine strawberries, granulated sugar, and vanilla extract. Set aside to allow the strawberries to release their juices.
04 - Roll out the dough on a floured surface to about 1/8 inch thick. Cut out circles using a cutter or glass.
05 - Place a teaspoon of the strawberry filling in the center of each circle. Fold the dough over to create a half-moon shape and pinch the edges to seal.
06 - Bring a large pot of salted water to a boil. Cook the pierogi in batches for about 5 minutes or until they float to the surface. Remove with a slotted spoon.
07 - For the sweet cream sauce, whip the heavy cream with powdered sugar and vanilla extract until soft peaks form.
08 - Serve the pierogi warm drizzled with sweet cream sauce.