Heat a Dutch oven or soup pot on medium-high heat.
Add in the broth, shrimp shells, ginger, garlic, soy sauce, fish sauce, star anise, brown sweetener, and cinnamon stick. Allow the mixture to come to a boil.
Lower the heat to medium-low. Cover and simmer for 20 minutes.
While the broth cooks, cook the noodles in accordance with the instructions on the packaging. When cooked, remove the noodles from water, rinse with cold water, dry and set them aside in your serving bowls. Drying them is important. You don't want them to become mushy.
Open the pot and use a strainer to strain the contents of the broth.
Add in salt and pepper to taste and taste the broth repeatedly to ensure it meets your taste.
Add in the bok choy and stir. Cook until it wilts.
Add in the shrimp and scallops. Cook for 1-2 minutes. I like to remove the seafood once cooked and add them to the serving bowls with the noodles. This ensures the seafood does not overcook.
Pour about 1 ½ cups of broth into each serving bowl with the noodles. Serve with toppings.