1/4 pound shrimp, shelled and deveined
1/2 pound boneless pork or chicken, such as shoulder, cut into large cubes
1/4 teaspoon ground white pepper
1/2 teaspoon salt
2 teaspoons cornstarch
2 teaspoons Shaoxing wine
1 teaspoon toasted sesame oil
1/2 teaspoon finely grated fresh peeled ginger
1/2 teaspoon sugar
1 package extra-thin wonton wrappers or regular wonton wrappers
1. In a medium bowl, cover shrimp with cold water and stir in baking soda. Refrigerate for 30 minutes. Drain and rinse shrimp under cold running water, then pat dry with paper towels.
2. Place the shrimp in a food processor and pulse 10 times, until coarsely chopped. Transfer shrimp to a large mixing bowl. Add pork to the food processor and pulse until finely chopped. Transfer pork to bowl with shrimp.
3. Add white pepper, salt, cornstarch, Shaoxing wine, sesame oil, olive oil, ginger, and sugar to the pork and shrimp, and, using a spatula or chopsticks, mix well until thoroughly combined. Set filling aside in the refrigerator for at least 30 minutes or overnight.
4. To wrap the siu mai, place 1 wonton wrapper in the palm of your hand. Place about 1 tablespoon of filling in the middle of the wrapper. Continue wrapping the remaining siu mai. The siu mai can be frozen now or cooked; note that frozen siu mai are best made without the carrot rounds on the bottom.
5. To steam, line your steamer basket or tray with parchment paper (Napa cabbage leaves can also work). Pour enough water into your steaming pot or wok so that the water is about 1 inch below the bottom of the steamer basket or tray. Bring to a boil.
6. Arrange siu mai in the steamer tray, leaving room around each one and steaming in batches if necessary. Steam fresh siu mai until cooked through, about 7 minutes.
7. Transfer to a plate. Serve. That siu mai are traditionally served without a dipping sauce, though if you prefer one, mix soy sauce with a little sesame oil and fresh scallions and serve alongside.