Add the broth, water, onion, garlic, star anise, whole cloves, ginger, and cinnamon, to a large pot and bring to a simmer. Cover and let simmer for 20-30 minutes.
Taste and add soy sauce as needed. The amount you need will vary a bit depending on your taste preference and how salty the broth you used is, I used 2 tablespoons.
Bring a big pot of water to a boil and cook your rice noodles. Follow the package directions or if there are none, cook until al dente, about 3 minutes. Drain, and rinse with cold water to stop the noodles cooking.
When everything is ready, serve by adding noodles to a bowl, using a ladle to collect the broth (leaving the onion and spices behind), and then top with garnishes of choice.