In addition, prepare the Bún Bò Huế broth is by simmering beef bones and pork bones. And lemongrass, onion, sharllot, ginger. While boiling broth in 6 to 10 hours to get the sweet taste from the marrow .And the shrimp paste “mam ruoc”, and very spicy chili oil is added later during the cooking process. So the right broth of Bún Bò Huế has color of chili oil, flavor of lemongrass and shrimp paste, the smooth sweet of bone marrow
Hue beef noodle soup usually includes medium cooked beef. That you add fresh beef straight to the bowl and add hot broth over it. And or beef shank, pig’s feet or pork meat. It can also includes cubes of pig or beef blood. Which has dark brown color. And a texture maybe same as black pudding. Sliced spring onion and onion is add on top
Local people eat Bún Bò Huế with mixing salad. Such as sliced banana blossom, lettuce, mint, basil, mung bean sprout. Fish sauce, lime wedge and fresh chili is also on the side. So you can add to the soup according to taste. Ingredients maybe depend on season and region due to their availability.
BÚN BÒ HUẾ - Vietnamese spicy beef noodle soup in Hue style-Hue Food
https://huecookingclass.com/vietnam-cuisine/bun-bo-hue-beef-noodle-soup/