Make Nuoc Cham Sauce: In a medium bowl, combine 1/4 cup of white sugar with 1/4 cup of fish sauce, 3 tablespoons of rice wine vinegar, 2 tablespoons of fresh lime juice, and 1/4 cup of water. Add minced garlic and, if desired, sliced chilis. Stir well until the sugar dissolves, and let sit for at least 10 minutes.

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

Prepare Meatballs: In a large bowl, combine pork mince, fish sauce, sugar, green onions, minced garlic, white pepper, and salt. Mix thoroughly and form into golf ball-sized meatballs.

Cook Meatballs: Heat oil in a skillet over medium-high heat. Cook meatballs for about 2–3 minutes per side, or until golden brown and cooked through, reaching 160°F (70°C).

Assemble Bowls: Divide soaked noodles into bowls, arrange meatballs on top, add fresh vegetables, and drizzle with Nuoc Cham sauce.