Cut the pork ribs into bite-sized pieces and rinse well. Place the ribs in a pot, cover with water, bring to a boil, then discard the water and rinse the ribs again. Add the ribs back to the pot, cover with fresh water, add a little salt, and simmer until tender. Peel the shrimp, set the meat aside, and use the shells to make a stock with 2 liters (about 8 1/2 cups) of water. Strain the shrimp stock and add it to the pot with the simmered ribs.

Finely chop, pound, or process the shrimp meat, then mix it with the pork paste. Season with 1 tablespoon fish sauce, black pepper, 1 teaspoon sugar, minced garlic and onion, and a little annatto oil. Mix well and let marinate for about 30 minutes.

To make the bánh canh noodles:
- Mix 400 grams (about 2 2/3 cups) rice flour with 650 ml (about 2 3/4 cups) water. Stir until smooth, then strain through a sieve for a fine batter. Pour the batter into a pot and cook over a double boiler on low heat, stirring constantly until the mixture thickens and becomes elastic. Let cool, then transfer to a food-safe bag and cut off a corner to pipe the noodles. Bring a pot of water to a boil, pipe the noodles into the boiling water, and cook until fully done. Remove, rinse with cold water, drain, and toss with a little cooking oil.

Sauté minced garlic and onion in a pan, then add a bit of annatto oil for color. Pour this mixture into the pot with the pork rib broth. Place the pot on the stove, add 1 1/2 teaspoons fermented shrimp paste while the broth is still cold to prevent a strong smell and enhance the flavor. When the broth comes to a boil, reduce the heat, skim off any foam, and season with 2 tablespoons seasoning powder and 2 tablespoons sugar.

Put the shrimp and pork paste mixture into a plastic bag with a cut corner. With the broth at a gentle simmer, pipe the shrimp mixture into the pot to form dumplings. Increase the heat to bring the broth back to a boil.

Next, add the bánh canh noodles to the pot and stir gently. Mix 50 grams (about 1/3 cup) tapioca starch with 200 ml (about 3/4 cup plus 1 tablespoon) cold water, stir until dissolved, and pour into the broth. Adjust the seasoning to taste and stir constantly until the broth thickens. When everything is cooked through, add chopped green onions and turn off the heat.

Finally, ladle the bánh canh into bowls and enjoy.