Heat the pot or work to medium/ high heat and dry fry the onion and ginger until it becomes slightly charred (about 4 minutes on each side).
Next pour in water, stock cube, chicken stock, bone broth, spices, sugar and fish sauce then cover and simmer for 30 minutes to let the flavours infuse.
While stock is simmering thinly slice the beef. To prepare the rice noodles; place them in a bowl and pour over water that has just been boiled. Leave for 10 minutes until soft but still firm and holding together.
After 30 minutes remove ginger, onion and spices from the pot so your are just left with the broth and bring to a rapid boil.
Divide noodles between the bowls and top with thinly sliced beef then ladle hot broth over the top until noodles and beef are submerged the beef will change colour as it goes from raw to cooked.
Serve steaming hot with bean sprouts, herbs, shallots, chilli, lime wedges and sauces in the middle of the table so everyone can help themselves and adjust to their tastes.