Clean the meat. Put 2 lbs of pork hocks, 2 lbs of beef shank, and 1 lb of beef chuck into a big soup pan and add water until it just covers the meat. Bring it to a boil. Once the water boils, remove it from the heat and pour out the water. Take out all the meat and set aside.
Add 3 cloves of garlic, 3 tbsp bun bo hue powder, 1 tbsp of shrimp paste and 1 tablespoon of oil to a soup pan. Cook for 30 seconds until fragrant. (You can use the same one you used to parboil the meat to save time.) Add in the beef shank and beef chuck, and cook until the beef is brown on all sides.
Add in water until it just covers the meat. I added 3 quarts or 12 cups of water. Bring to a boil, and scoop away any impurities that you see.
Lower the heat, and add the pork hocks back to the pot. Also, add 1 onion, 1 daikon, and 2 stalks of lemongrass. Simmer for 2-3 hours.
After 2 hours, check that the meat is cooked through. Leave them in the broth if they need to be cooked more. Once cooked through, take out the meat. Slice the beef and set aside. The beef is cooked through once it's tender and falls off the bone.
Add 2 tsp of salt, 2 tbsp of fish sauce, 1 tbsp of sugar, and 1 can of chicken broth to the soup. Simmer the soup for another 15 minutes.
While the soup is simmering, make the sate chili. Combine 1/4 cup of vegetable oil and 2 tsp of annatto seeds in a small sauce pan. Cook for 1-2 minutes until the oil turns red. Discard the seeds and add the rest of the ingredients for the sate chili to the pan. Cook for 1-2 more minutes and remove from the heat.
After 15 minutes of simmering, add 1-2 tbsp of the sate chili to the broth and stir. Alternatively, serve it on the side and allow guests to add it to their bowl.
Taste the soup and see if it has enough flavor. If not, add more fish sauce until it tastes just right. Turn off the heat.
Now it's time to assemble your bowls of soup! Grab a handful of cooked noodles and put them in a bowl. Top it with some of the beef slices, a piece of the pork hock, cilantro, green onions, bean sprouts, cha lua, and a small teaspoon of shrimp paste (optional). Ladle some soup over these yummy ingredients and serve.