Combine ground pork, minced ginger, Shaoxing wine, light soy sauce, 1/4 teaspoon salt, and egg white in a small bowl, mix well. Add 2 tablespoons water, mix until water is fully incorporated. Blend in cornstarch and mix until the ground pork becomes pasty.

Prepare winter melon. Use a knife to slice the rind off and discard it. Divide melon into 4 equal parts, then further into 8 parts. Cut off the inner soft part and discard it. Flip the winter melon so that it’s skin side down, and slice along the cut side to make evenly thick pieces.

Add pork broth to a medium-sized pot and bring to a boil. Turn to low heat. Use a spoon to scoop about 1 tablespoon of the ground pork mixture to shape it into a ball, and add it to the soup. Make the meatballs one at a time. After the last meatball is added, 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.

Transfer 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, 5 to 8 minutes. You can try a piece of winter melon; if the texture has begun to turn soft, it’s cooked.

Add meatballs back into the soup. Bring the soup back to a boil and cook for 1 minute. Turn off heat, cover, and allow soup to sit for another 5 minutes. Add the remaining 1/2 teaspoon salt or to taste, and mix well.

Add cilantro to the soup and serve warm.