Heat the sesame oil in a large pot set over medium heat. Add the star anise, garlic, and ginger; heat until fragrant, about 30-60 seconds. Pour in the broth, shrimp shells, soy sauce, hoisin sauce, fish sauce, lime juice, and sliced jalapeño. Bring to a boil, then reduce the heat to low and simmer for 20 minutes with the pot covered 3/4 of the way.
While the broth is simmering, cook the noodles according to package instructions. Drain in a strainer, then rinse the noodles with cold water until they are no longer warm to prevent them from continuing to cook. (I also recommend tossing the noodles with a drizzle of oil, like sesame oil, to prevent them from sticking.)
Using a slotted spoon, carefully remove the shrimp shells and discard.
Add the bok choy and shrimp to the broth and cook for 3-4 minutes, until the shrimp are fully cooked and opaque.
Divide the noodles between bowls and ladle the soup over top, garnish and serve hot.
Notes
Shrimp shells can also be wrapped in a cheese cloth for easy removal.
Cooking rice noodles is similar to cooking pasta. First bring a large pot of water to a rolling boil. Place the noodles in the water and stir with a fork to prevent them from sticking.
When the noodles are tender, remove from heat and drain. Then rinse immediately with cold water until the noodles have completely cooled.
This stops the cooking process so the noodles don’t overcook. Don’t worry, the broth will heat the noodles back up!
The amount of noodles you make will affect the cook time, so keep an eye on them.
Here are some other options if you can't find pho noodles:
Pho: Pho noodles are one of the most well-known Vietnamese noodles. These noodles are flat, rather than string shaped. There are several different types of pho that are differentiated by the meat: (chicken), Pho Bo (beef), and Pho Xao (stirred pho).
Bun (Rice Vermicelli): This is one of the most popular Vietnamese noodle types. They can be very thin or very thick and are often found in Bun Cha, Bun Thit Nuong, Bun Bo Hue, and Bun Rieu.
Banh Canh: These noodles have a chewier texture, as they are made from a mixture of tapioca flour and rice flour. They are thick like udon noodles, but it’s important to note that udon noodles are made from wheat flour.
Mi (Egg Noodles): Typically used in stir-fry, these noodles are pretty easy to find and affordable. They are a thin, yellow egg noodle that can be combined with various ingredients.
Mien (Glass Noodles): Depending on where you are, these noodles might also be referred to as Chinese Bun. They are grey in color and opaque, with a chewy but slippery texture from the mixture of mung bean flour and tapioca flour in which they are made from. You might find these in soups or stir-fries