In a bowl, mix together the marinade ingredients. Add the sliced pork belly and let it marinate for at least 30 minutes.
Prepare the noodles according to the package instructions. Drain and set aside.
In a separate pot, bring the broth to a simmer. Add the soy sauce, fish sauce, and sugar. Keep it warm on low heat.
Heat a pan over medium heat and cook the marinated pork belly until it turns brown and crispy. Set it aside.
In the same pan, add the bean sprouts and sauté them for a few minutes until they become slightly tender.
To serve, divide the cooked noodles among bowls. Top each bowl with the sautéed bean sprouts, crispy pork belly, crushed pork rinds, and fresh herbs.
Ladle the warm broth over the noodles and garnish with lime wedges.
Serve the Cao lầu hot with chili sauce on the side for those who prefer a spicy kick.