Preheat oven to broil and bake the onion for 20 minutes until it is charred on the outside. Set aside.
Soak dried shrimp in water for 10 minutes. Set aside.
Parboil the pork shoulder to clean the meat. Add pork to a soup pot. Cover with water so that it just covers the pork. Bring to a boil and simmer for 10 minutes. Take out the pork and throw out all your water. Clean the pot and run the pork under water to clean off any gross bits. Add the pork back to the clean soup pot.
Make the broth
Now you’re ready to make your broth. Add the broiled onion, dried shrimp, daikon, and salt to the pot. Add water until it just covers all the ingredients. Bring to a boil and simmer for 45 minutes. During this time, make sure to check on the soup every 15 minutes to scoop away impurities.
While your soup is simmering, prepare your toppings. Boil your shrimp and banh canh. Set aside.
After simmering for 45 minutes, the meat should be done. Separate the meat from the bones and add the bones back to the pot. Cut the meat into bite-sized pieces and set aside.
Add the fish sauce and chicken broth powder and simmer for 30 minutes.
While the broth is simmering, make your annatto oil. Combine annatto seeds and vegetable oil in a sauce pan and simmer for 1-2 minutes until the oil turns orange. Set side.
Mix the tapioca starch with 2/3 cup of water. Once the soup is done simmering, add the tapioca starch slurry. Let the soup simmer for 5 minutes to thicken.
Lastly, add in the annatto oil and your soup is done.
Put together your noodle bowls
Now it’s time to put your noodle bowls together. Add noodles to a bowl. Top with pork shoulder, crab meat, shrimp, fried shallots, and minced green onions and enjoy!
Notes
Store the components for this noodle bowl separately in the fridge for up to 3 days. When you're ready to serve, heat up the soup and microwave the noodles, then put it all together with the toppings.