Combine soy sauce, sugar, and vinegar in a small saucepan over low heat. Stir for about 3–5 minutes until the sugar dissolves completely and the sauce is slightly thickened. Set aside to cool.

In a medium skillet, heat a splash of oil over medium heat. Add chicken, beef, or tofu and cook for about 5–7 minutes until each side is golden. Remove from heat, cool, and shred or slice.

Bring a large pot of water to a boil. Add rice noodles and cook according to package instructions (about 6–8 minutes). Drain, rinse under cold water, and toss with a drizzle of oil.

Wash and dry the fresh herbs and vegetables. Thinly slice the cabbage, lettuce, and carrots; chop the cilantro, Thai basil, and mint. Set aside in a large mixing bowl.

In a large serving bowl, combine the cooled noodles with the tangy-sweet sauce. Add the sliced protein, chopped vegetables, and herbs, and toss everything until evenly coated.

Transfer the completed Pho Tron to bowls or a platter. Just before serving, sprinkle on toppings like fried shallots, peanuts, and chili.