Clean the pork hock and blanch in boiling water. Measure 7 bowls of water (about 14 cups/3.3 liters) and simmer the pork hock until tender. Boil the crabs, crack the claws and set aside. Sauté the crab roe with shallots and annatto oil until fragrant. Clean the mushrooms.

Once the pork hock is tender, remove it from the broth. Season the broth to taste, then add the shrimp. Sauté annatto oil and add it to the broth. Lightly sauté the mushrooms with annatto oil as well.

After prepping all ingredients and seasoning the broth, add the mushrooms and shrimp to the broth. Gradually mix the tapioca starch with water and slowly pour it into the broth, stirring until the broth thickens. Blanch the banh canh noodles. Slice cilantro, green onions, onion, lime, and chili.

To serve, place the banh canh noodles in a bowl. Top with pork hock, crab claws, shrimp, crab roe, a few slices of Vietnamese pork sausage, cilantro, fried shallots, and pour the hot broth over. Serve immediately for best flavor.