Combine the ground pork, Shaoxing wine, light soy sauce, minced ginger, salt, egg white and water in a medium-sized bowl. Stir with a spatula to mix well. Add the cornstarch. Mix until the ground pork becomes pasty and sticky. Set aside to marinate.

To prepare the winter melon. Chop it into 3 to 4 pieces. Use a knife to slice the rind off and discard it. Cut off the soft inner part and discard it. Slice the winter melon into even 1/2” (1 cm), large bite-size pieces.

Add the broth and ginger (if using) to a medium-sized pot and bring to a boil over medium-high heat. Turn to medium-low heat. Use a spoon to scoop about 1 tablespoon of the ground pork mixture, shape it into a ball, and add it to the soup. Make the meatballs one at a time. After the last meatball is added, cook for 1 minute. Stir the soup gently 2 to 3 times. Immediately transfer all the meatballs to a plate and set aside. The meatballs should be cooked on the outside but still raw inside.

Add the winter melon to the pot. Bring the soup to a boil over high heat. Turn to medium heat and boil until the winter melon is almost cooked through, 6 to 8 minutes. The edges of the winter melon should have turned semi-transparent.

Add the meatballs back into the soup. Bring the soup back to a boil and cook for 1 minute. Turn off the heat, cover, and allow the soup to sit for another 5 minutes. The residual heat will further gently cook the meatballs so they remain super tender and juicy. Add the salt and mix well. Taste the soup and adjust seasoning if needed.

Add cilantro to the soup and serve hot.