Prepare the Nuoc Cham Sauce: In a mixing bowl, combine white sugar, fish sauce, rice wine vinegar, lime juice, water, minced garlic, and any desired chilis. Stir well until the sugar is fully dissolved. Let the sauce sit for about 10 minutes.

Cook the Noodles: Bring a pot of water to a boil and add vermicelli noodles. Soak according to package instructions (around 5-7 minutes). Drain and rinse under cold water, then set aside.

Make the Meatballs: In a large bowl, mix together pork mince, fish sauce, white sugar, green onions, garlic, white pepper, salt, and optional lemongrass. Form into 12-16 golf ball-sized meatballs.

Cook the Meatballs: Heat oil in a skillet over medium-high heat. Add meatballs, ensuring space between them. Sear for 2-3 minutes on each side until cooked through and golden brown.

Assemble Bowls: Place vermicelli noodles in bowls, top with meatballs, arrange fresh vegetables, and drizzle Nuoc Cham sauce over the dish.