Ingredients For the filling:

3 small dried shiitake mushrooms (or 1-2 large)
1/2 cup hot water
8 ounces peeled and deveined shrimp (any size)
4 teaspoon teaspoons sugar (divided)
1/8 teaspoon baking soda
2 tablespoons water
1 pound ground pork
1 tablespoon cornstarch
1 tablespoon Shaoxing wine
1 teaspoon salt
1/4 teaspoon white pepper powder
1 tablespoon neutral oil
1 tablespoon oyster sauce
1/2 teaspoon sesame oil

For assembling the siu mai:

24 thin Hong-Kong-style round dumpling wrappers (or thin Hong-Kong-style square wonton wrappers)
2 tablespoons very finely minced carrot
chili garlic sauce or chili oil (for serving)

Instructions

Make the filling:

Soak the shiitake mushrooms in the hot water for 2 hours (or overnight) until fully rehydrated. Squeeze any excess water out of the mushrooms. Trim away any tough stems, and very finely chop the mushrooms—you should have about ¼ cup.
Add the shrimp to a medium bowl, and toss them with 1 teaspoon of the sugar, the baking soda, and the 2 tablespoons of water. Set aside for 15 minutes, then rinse the shrimp in a colander under running water until the water runs clear. Drain.
Meanwhile, to the bowl of a stand mixer fitted with the paddle attachment (or just a large bowl, if mixing by hand), add the ground pork, the remaining tablespoon sugar, the cornstarch, Shaoxing wine, salt, and white pepper. Mix on medium-low speed for 5 minutes, or until the mixture resembles a paste that sticks to the sides of the bowl. (Alternatively, mix vigorously in one direction with a pair of chopsticks by hand for 10 to 15 minutes until you get the same result.)
Scrape down the sides of the bowl, add the shrimp, and beat on low speed for 2 minutes. Increase the speed to medium and beat until the shrimp is well incorporated into the pork, another 2 minutes. (If mixing by hand, roughly chop the shrimp, add them to the pork, and mix in one direction for 10 minutes.)
Add the chopped mushrooms, the neutral oil, oyster sauce, and sesame oil. Mix on medium speed for 1 minute (or by hand for 2 to 3 minutes).

Assemble the siu mai:

Line a bamboo steamer with perforated parchment paper, damp cheesecloth, or thin cabbage leaves. Take one wrapper and place a tablespoon of filling in the middle. Squeeze the sides of the wrapper up around the edges of the filling to create an open-topped pocket. Use a butter knife to continue filling the wrapper until it’s stuffed to the top with filling, and then scrape the top flat. If using square wrappers, fold over any excess wrapper and squeeze the wrappers to the sides of the siu mai.
Continue until you’ve assembled all the siu mai, transferring them to the lined steamer basket as you go, placed 1 inch apart. (Place any siu mai that don’t fit in the steamer on a parchment-lined plate or sheet pan to cook in later batches or freeze.) Top the center of each siu mai with a small amount of the minced carrot.

Steam:

Fill a wok with enough water to submerge the bottom rim of your bamboo steamer by ½ inch (you may need to add more boiling water during steaming to keep the water at this level). Bring the water to a simmer over medium-high heat. Place the covered steamer in the wok and steam each batch over medium heat for 9 minutes. Serve with the chili oil or chili garlic sauce.

Notes

Recipe makes about 2 dozen siu mai. Nutrition info is for one serving, or about 3 siu mai. Nutrition info does not include chili garlic sauce or chili oil condiment.