Separate out ⅓ of the shrimp and chop it into chunks that are the size of large peanuts.
390 grams shrimp
Mince up the remaining shrimp until you have a rough paste.
Slice the cuttlefish into ⅛-inch strips, and then chop up the strips. Next, mince up the chopped cuttlefish until you have a rough paste.
100 grams cuttlefish
For the pork fat, slice it up as thinly as possible. Cut the slices into thin strips, and then mince the strips up into cubes that are about 1/16-inch in diameter.
50 grams pork fat
Add the shrimp, cuttlefish, pork fat, scallions, egg white, potato starch, oyster sauce, ginger juice, Shaoxing wine, toasted sesame oil, soy sauce, and white pepper to a bowl and beat the mixture together with your hand until it starts to firm up and get frothy. Cover the bowl and refrigerate for at least 1 hour, preferably overnight.
50 grams scallions, 1 tablespoons egg white, 2 teaspoons potato starch, 1 tablespoon oyster sauce, 2 teaspoons ginger juice, 2 teaspoons Shaoxing wine, 1 teaspoon toasted sesame oil, 1 teaspoon soy sauce, ¼ teaspoon ground white pepper
Line a steamer with a layer of lettuce leaves.
lettuce (for lining the steamer
To shape the Shumai, place a wrapper on the top of your hollowed-out fist, and then use a spoon to press the filling into the center of the wrapper to press it down into the hole you've made with your hand.
42 Shumai wrappers
Turn the Shumai a few times to set the pleats, flatten off the bottom, and then place the dumpling on the lettuce-lined steamer. Leave space between each dumpling and repeat until you've filled up the steamer.
Bring a pot of water that will hold your steamer basket to a boil, and then set the covered steamer on top (or inside). Adjust the heat to maintain a steady stream of steam escaping and steam the Shumai for 7-8 minutes.
To make the dipping sauce, mix the black vinegar, soy sauce, and ginger together in a bowl.
2 tablespoons black vinegar, 1 teaspoon soy sauce, Ginger
Garnish the Shumai with a small mound of tobiko, and serve with the dipping sauce.