Start by parboiling your pork hock, pork neck bone, and oxtail. Next, pour out your bones and rinse off all the grimy stuff.

Place bones in Instant Pot with lemongrass stalks and onions. Fill pot with enough water to cover everything. Set Instant Pot to manual for 20 minutes. Let natural release for 10 minutes, then quick release any remaining pressure.

Remove bones and onions from Instant Pot and set the bones aside. Add beef shank to the pot with salt, shrimp paste, fish sauce, and rock sugar. Place the lid back on the Instant Pot and set to manual for 60 minutes. Let natural release for 10 minutes, then quick release remaining pressure.

While your beef shank is cooking, boil water and add noodles. Cook for 10 minutes or until noodles are cooked through. Drain the water and set noodles aside.

Heat a pan over medium heat and add the oil and annatto seeds. Cook for 1-2 minutes. Remove the annatto seeds (I poured the oil and seeds through a strainer and poured the oil back into the pan). Add the shallots to the oil and cook for 1-2 minutes, then add the remaining aromatics. Cook until mixture becomes fragrant. Remove from heat and set aside.

When your beef shank is done, remove it from the pot, and switch the Instant Pot to saute. Pour the aromatics and oil into your pot and wait for the soup to boil.

Drop dollops of fish paste into the boiling soup. The fish paste will float to the top when they are done.

Slice your beef shank into thin slices.

Assemble your bowl by adding noodles, cha lua, and beef shank. Ladle broth and fish paste into your bowl. Eaters can add bean sprouts and mint as they please. I recommend squeezing some lime over everything!