Place the beef shanks in a saucepan, cover with water and bring to a boil.
To give the broth its characteristic brown color, the onion and spices need to be charred. Heat a dry frying pan over high heat and place the white onion and ginger halves, cinnamon, cloves, star anise, black peppercorns, and coriander on it. Fry the onion on both sides until characteristic black stripes form, remember to stir the spices.
When the beef broth boils, remove the foam and add the ingredients from the frying pan to the meat. Cook the contents of the pan for two hours over low heat.
After two hours, remove the beef shanks from the pot and lower the beef fillet into the broth. Add fish sauce, sugar and salt to the pot. Bring the broth to a boil and simmer the meat for one and a half to two hours over low heat.
While the meat is cooking, prepare the vegetable component of the soup. Cut the red onion into half rings, cut the chili pepper into slices, chop the Chinese cabbage into strips, and cut the onion stems into thin strips.
Cook rice noodles according to package instructions, drain in a colander, and cool in cold water for a few minutes.
Remove all ingredients from the pan and strain the broth. Place the beef fillet on a cutting board.
Remove the shanks from the bowl and separate the meat from the bones and connective tissue. Cut the beef fillet and shanks into thin slices.
Assemble the soup. Place rice noodles on the bottom of the bowl, arrange the beef slices in a semicircle, add onions and green onions to the bowl, and pour the beef broth over the contents of the bowl.
Add Chinese cabbage, chili pepper, mint leaves and parsley to the soup. Sprinkle the finished soup with lemon juice and serve. Enjoy!