For the Pho stock, add the 6 cups of beef stock to a sauce pot and bring to a slow boil.
Add the fish sauce, sugar, ginger, onion and salt.
Reduce the heat and simmer.
Add the cloves, star anise, and cinnamon stick. Simmer for 30 minutes.
Taste stock and adjust seasoning. Strain the stock and return to sauce pot. Reserve for assembly.
For the assembly:
In a separate pot bring water to a boil. Place rice noodles in water for 30 seconds (or according to package instructions), then strain and distribute between 4 bowls.
Top each bowl with sliced beef, basil, bean sprouts, scallions, and onions. Ladle in enough broth to cover the ingredients in the bowl.
Serve with lime wedges sriracha and hoisin.