For the Beef Broth: In a large stock pot, combine oxtail and beef neck bones. Cover with 2 inches of water, set over medium-high heat, and bring to a boil; boil for 5 minutes. Strain bones into a colander, discarding the water, then carefully wash bones under cold running water, removing any bits of scum, any visible marrow in the bones, or coagulated blood. Wash pot.

Return bones to the pot with 5 quarts (4.75L) water, along with a large pinch of kosher salt, the soy sauce, Thai black soy sauce, rock sugar, brown sugar, cinnamon stick, Sichuan peppercorns, star anise, coriander seeds, pickled garlic, whole white peppercorns, shallots, cilantro roots, garlic, pandan leaves, daikon radish, and galangal. Bring to a boil over high heat, then reduce heat and simmer until beef is tender and the broth is reduced by half, about 3 hours.

Using a countertop or immersion blender, blend 1 cup (240ml) beef broth with the fermented beancurd and fermented soybean paste until combined. Return to stockpot, then add ground white pepper and five-spice powder. Return to a simmer and cook for 10 minutes.

Using tongs, transfer oxtail and beef neck bones to a large heatproof bowl and set aside to cool. Using a fine-mesh strainer, strain broth into another large heatproof bowl; you should have about 2 quarts (2L) broth (this is more broth than you will need for the 4 servings this recipe yields; save the rest for future bowls or prepare more toppings than what is instructed in this recipe to make more than 4 bowls ).

When the oxtail and neck bones are cool enough to handle, pick the meat from the bones and discard any excess fat. You should have about 11 ounces (340g) each of oxtail and neck bone meat. Add ¼ cup (60ml) broth to the picked meat to moisten and keep warm.

For the Roasted Chile Vinegar: In a medium stainless-steel or cast iron skillet set over medium heat, cook chiles until charred on both sides, about 5 minutes. Transfer chiles to the bowl of a food processor and set aside. Add garlic to the skillet and cook until well browned on both sides, about 5 minutes. Add galangal and cook, stirring constantly to prevent garlic and galangel from burning, until slightly dried out, about 3 minutes.

Transfer garlic and galangal to food processor along with ½ cup (118ml) distilled white vinegar and pulse until a fine paste forms. Transfer mixture to a medium bowl and whisk in remaining ½ cup (118ml) vinegar along with the salt. Set aside.

For the Boat Noodle Seasoning: In a medium bowl, whisk together granulated sugar, distilled white vinegar, fish sauce, roasted chile vinegar, and roasted chile powder until well-combined. Set aside.

To Assemble: Add 2 cups (475ml) beef broth to a 1-quart saucepan along with the beef meatballs and bring to a boil, then reduce heat to a simmer and cook, covered, until meatballs are fully heated through, about 5 minutes. Remove from heat and keep warm.

Add garlic oil to a heatproof medium bowl and set aside. In a pot of boiling water, cook noodles according to package instructions. Drain noodles, then transfer to bowl with garlic oil and toss to coat. Divide noodles among 4 serving bowls.

Add the ¼ cup (60g) boat noodle seasoning to a second heatproof bowl. Using a slotted spoon, transfer meatballs to the serving bowls, then return broth to heat and bring to a bare simmer. Stir in pork or beef blood, if using; make sure broth doesn't get so hot that blood coagulates. Stir broth into bowl with boat noodle seasoning.

Divide reserved beef and blanched morning glory among bowls. Ladle broth over the noodles and meat and serve immediately with crispy fried garlic, boat noodle seasoning, chile flakes, fish sauce, roasted chile vinegar, pork cracklings, Thai basil leaves, and sugar alongside.