Cut the beef tendon into bite-sized pieces. Blanch in boiling water with a little salt and smashed ginger, then rinse clean. Marinate with 2 tablespoons fish sauce and 1/2 tablespoon sugar. Toast the onion, ginger, cardamom, star anise, and cinnamon until fragrant. Smash the ginger, onion, cardamom, and lemongrass, then add to the beef and mix well. Let marinate for 20-40 minutes.

Sauté the beef tendon in a pot until slightly browned, then add water and simmer on low heat for 30 minutes or until the tendon is tender to your liking. Add more water as needed and season to taste. This will be your broth.

Thinly slice the beef brisket and marinate with a little fish sauce and julienned ginger. Soak the dried rice vermicelli noodles until softened, then boil until cooked and set aside. Chop the scallions and culantro, thinly slice the onion, and set aside.

To serve, add noodles to a bowl, top with blanched brisket, braised tendon, scallions, culantro, onion, and a few slices of fresh chili. Ladle hot broth over and enjoy.