Combine first 7 ingredients in a pan and cook over medium heat until soft (about 15 minutes).
Cut the dough into 4 equal pieces, then roll each piece into 1- inch-thick logs (they will be about 6-8 inches long). Using a sharp knife, cut the logs into eight 1-inch pieces. Using a rolling pin, roll the pieces into 2-inch rounds, keeping the dough covered with a clean towel as you work to prevent the dough from drying out. Dust the rolling pin occasionally with flour to prevent sticking.
Place about 1 tablespoon of the filling in the center of each round, then fold over one side to form a half circle, pressing to adhere, or pleating decoratively along the edge to seal. Place filled dumplings on the prepared baking sheet and cover with plastic wrap while you prepare the rest.
Bring a large pot of water to a boil. Cook dumplings in batches of about 8 until they are cooked through, 3 to 4 minutes. Using a slotted spoon, transfer the dumplings to a serving platter. Serve warm with the dipping sauce.
NOTE: The assembled dumplings can be frozen for up to 2 weeks.