Make the meatball mixture

• In a mixing bowl, combine the ground pork, green onion, grated ginger, grated garlic, soy sauce, sesame oil, white pepper, rice vinegar and cornstarch.
• Mix until just combined, then form into small meatballs about 1 inch in diameter.
• Set the meatballs aside.

Sauté the aromatics

• Heat the sesame oil in a large pot over medium heat.
• Add the onion, smashed garlic, sliced ginger and lemongrass paste.
• Sauté until the aromatics are fragrant, adding a drizzle of oil if needed to prevent burning.

Build and simmer the broth

• Pour in the chicken broth.
• Season with soy sauce, rice vinegar, sesame oil, white pepper, a pinch of salt and the fish sauce if using.
• Bring to a boil, then reduce the heat and simmer.

Strain the broth

• Strain the broth to remove the onion, garlic and ginger.
• Return the broth to the pot.

Cook the meatballs

• Bring the broth back to a simmer.
• Gently drop in the meatballs and cook until cooked through and floating on top.

Add wonton wrappers and bok choy

• Gently drop in the wonton wrappers in batches so they don't stick together, and cook until they float to the top.
• Add the bok choy and cook until wilted but still retaining some texture.

Taste and adjust

• Taste the soup and adjust the seasoning with soy sauce, rice vinegar, chili oil or fish sauce as needed.

Serve

• Ladle into bowls and garnish with a drizzle of chili oil and green onions.