1.Preheat oven to 220ºC.
2.Combine beef bones, onion, carrot and celery in a large baking dish; roast, uncovered, about 45 minutes or until browned all over. Drain excess fat from dish.
3.Combine beef mixture, cinnamon, star anise, cardamom, peppercorns, fish sauce, cloves, ginger, garlic, gravy beef and the water a in large saucepan; bring to the boil. Reduce heat; simmer, uncovered, 1 1/2 hours, skimming occasionally. Strain through a muslin-lined sieve or colander into a large heatproof bowl. Reserve broth and beef; discard solids.
4.When beef is cool enough to handle, shred meat finely. Return beef to cleaned pan with soy sauce and broth; bring to the boil. Season to taste.
5.Just before serving, place vermicelli in a large heatproof bowl; cover with boiling water. Stand for 3 minutes; separate with a fork, drain.
6.Divide vermicelli among serving bowls; top with broth and beef mixture, mint, chilli, extra onion and coriander. Serve with sprouts.
This is Vietnam’s famous beef noodle soup.Note