Step 1

Bring 2 cups of water to a boil in a medium saucepan. Add the mushrooms, turn off the heat, cover and soak until rehydrated, about 30 minutes.

Step 2

Drain the mushrooms and remove and discard the stems. Finely dice the mushrooms; set aside.

Step 3

Whisk 4 cups of cold water and 1 tablespoon of the baking soda in a large bowl until the baking soda is dissolved. Lightly massage the shrimp in the baking soda water and let soak for 30 minutes.

Step 4

Drain the shrimp, rinse under cold running water, drain again and pat dry with paper towels. Roughly chop the shrimp into 1/2-inch pieces; set aside.

Step 5

Coarsely chop the pork belly into approximately 1/2-inch pieces (they don't have to be perfect). Continue to chop until it resembles coarsely ground pork (but don't chop it so finely that it becomes smooth). Transfer the pork to a large bowl and fill with enough cold water to cover. Let soak until the water turns pink, about 5 minutes. Drain the water and repeat the soaking process once more until the pork is a bit opaque. Drain and pat dry with paper towels. Reserve the bowl.

Step 6

Transfer the pork back to the bowl, sprinkle with 1 teaspoon cold water and the remaining 1/4 teaspoon baking soda and mix until the baking soda is absorbed. Mix in the reserved shrimp until combined. Add 1 tablespoon salt to the pork and shrimp filling and mix in one direction until the mixture is sticky and leaves streaks along the sides of the bowl, about 3 minutes. Gather the filling in one hand, lift it up and away from the bowl and throw it back into the bowl. Repeat 9 additional times to help bring the filling together and produce the desired texture.

Step 7

Add the sugar, chicken powder, soy sauce and white pepper to the filling and stir until combined. Add the reserved mushrooms and lard and mix until combined. Cover and refrigerate for 1 hour.

Step 8

Cover the wonton wrappers with a damp paper towel to prevent them from drying out. Using your nondominant hand, put your index finger and thumb together to form a circle and place 1 wonton wrapper on top of the circle. Spoon a heaping tablespoon of the filling into the center of the wrapper and use the spoon to pack in the filling while gently squeezing on the sides to form the wrapper around the filling. Add a little more filling if it doesn’t reach the top of the dumpling (see Cook's Note). Place the siu mai on a parchment-lined plate or tray. Repeat with the remaining wrappers and filling.

Step 9

If desired, top each siu mai with a pea-size scoop of flying fish roe or minced carrot (a little less than 1/8 teaspoon) or 1 frozen pea.

Step 10

Fill a 12-inch skillet or wok with about 2 inches of water and place a 10-inch bamboo or metal steamer basket in the skillet. Make sure the water doesn’t touch the bottom of the insert. If it does, remove some of it. Bring the water to a rolling boil, line the steamer basket with a perforated parchment circle and place 10 siu mai on the parchment, leaving an inch between each. Cover and steam until the filling is opaque and the wrapper is translucent, about 10 minutes. Enjoy while hot. Continue with the remaining siu mai.