For the Sauce:
½ cup soy sauce
½ cup black vinegar
1 tablespoon sesame oil
2 teaspoons toasted white sesame seeds
For the Shrimp Dumplings:
1 pound large shrimp–shelled, deveined and diced
2 teaspoons minced lemongrass (optional)
1 teaspoon minced garlic
1 teaspoon cornstarch
1 teaspoon sugar
1¼ teaspoon salt
Thirty 3½-inch round dumpling wrappers (see note above)
1. Make the sauce: In a medium bowl, combine all the ingredients and set aside until ready to serve. Makes about 1 cup.
2. Make the shrimp dumplings: In a medium mixing bowl, combine the shrimp, lemongrass, garlic, cornstarch, sugar and salt. Cover and refrigerate for 2 hours.
3. Working with one dumpling wrapper at a time, place a tablespoon of the shrimp filling in the center of the wrapper and fold in half. Pinch the dumpling at one end before guiding one edge over and folding it to form a pleat, making sure to pinch as you go until you have a total of 6 pleats and the dumpling is closed. Transfer the dumpling to a parchment-lined baking sheet. Repeat with remaining dumpling wrappers until all of the filling has been used. Cover the dumplings with a damp paper towel until ready to cook.
4. To cook the dumplings, bring 1 cup of water to a boil in a large skillet. Place a 9-inch 3-tiered bamboo steamer lined with parchment paper or lettuce over the water.
5. Working in 3 batches, cover and steam the dumplings until cooked through, about 5 minutes. Serve immediately with the dipping sauce.