In a pan on medium-high heat, toast the cinnamon, clove, star anise, fennel seed and coriander seeds. Set aside.
Place halved onions and ginger ona metal tray. With a blow torch, char onions and ginger until blackened on all sides.
(Toasting spices will bring out the flavour of the spices. If you do not have a blowtorch, place halved onions and ginger over a metal wire rack and place directly on flame from gas stove, turning occasionally until charred and blackened on all sides.
In a pot on high heat, boil 4L water and add charred onion, ginger and toasted spices with ½ tsp salt, 1 tbsp sugar and 2 tbsp fish sauce.
Bring mixture vigorous to boil before reducing to low heat for 10 minutes.
Add blanched meat to the soup stock and let it simmer on low heat for 3 hrs, skimming fat and solids occasionally by using a ladle to remove the foam on the surface.
After 3 hrs, use a sieve to remove onion, ginger and spicesand let it simmer for another 3 hrs.
About 6 hrs later, the broth should be reduced to half. Transfer meats into a bowl and remove flesh from bones. Place the bones back into broth.
(Blanch the oxtail and beef shins in boiling water for 15 min until scum surfaces. Remove oxtail and shins from potand rinse it under cool running tap water. To reduce cook time, you can substitute 4L water, beef oxtail and shins with 4L beef stock.)
In a serving bowl, place blanched pho noodles, beef, raw sukiyaki beef and ladle over with hot broth. Serve hot with mint leaves, coriander, Thai basil, lime slices, bean sprouts and cut chilli on the side.