Wash oxtail bones with cold water
Char the white onions and ginger root
Toast the coriander seeds, star anise, cardamom pods, cloves, fennel seed, and cinnamon stick
Add oxtail to a pot with water and bring to boil
Skim impurities from the broth
Add charred onions, ginger, and toasted spices to the broth
Simmer the broth for at least 3-4 hours (or up to 6 hours)
Add palm sugar, salt, and chicken/pork seasoning powder
Season at the end with fish sauce or phở stock cubes to prevent sourness
Wash phở noodles with cold water
Cook noodles according to package instructions
Assemble bowls with noodles and ladle hot broth over top
Garnish with coriander, spring onions, Thai basil, mint, bean sprouts, lime, chillies, and pepper
Serve with dipping sauce of sriracha, hoisin sauce, fish sauce, chili oil, and lime
