1.In an electric mixer fitted with the paddle attachment, add the ground beef, cold water, and baking soda. Turn the mixer on slow speed for 10 minutes. You’ll see that there may be bits of fascia/meat fibers that stick to the paddle as the beef is mixed, remove these as you see them. Scrape the sides of the bowl to ensure the meat and fat are evenly incorporated.
2.Add the ginger, green onions, sugar, salt, cornstarch, 1 tablespoon vegetable oil, sesame oil, rice wine, white pepper, tangerine peel, coriander, and egg white. Stir on medium speed for 15 minutes.
3.Again, stop the mixer every 5 minutes and remove any tough fibers or membranes from the paddle attachment. These tough pieces tend to cling to the paddle during mixing. Remove the bowl from the mixer cover and place in the fridge overnight.
4.When you’re ready to steam the meatballs, bring a pot of water to a boil and add 1 teaspoon vegetable oil. Take 1 bunch of watercress and blanch for 30 seconds. Drain, rinse in cold water, and squeeze out all the liquid. Very finely chop the watercress.
5.Add the finely chopped watercress and cilantro to the meat mixture, and fold in by hand until everything is evenly incorporated. Lay down a bed of fresh watercress on a heatproof plate that you’ll use for steaming. Using oiled hands, portion the meat into 60 gram chunks, and roll them into round meatballs.
6.Set up your steamer. Once the water is boiling, steam the meatballs on high for 12 minutes. Remove from steamer and enjoy immediately.