Heat a large soup pot over medium-high heat.

Follow first three steps.

Bring to a boil, reduce heat to simmer, and cover. Cook for 60-90 minutes, stirring occasionally.

Taste and cook another 30-60 minutes if needed to develop flavors.

Add the beef to the freezer for 10 minutes easier slicing.

Slice very thinly against the grain, set aside.

Boil 8 cups water and pour over noodles. (Follow noodle package instructions). Drain and transfer to bowls.

Serve noodles in a bowl and top with sliced beef. Pour boiling broth over beef and noodles, so the beef cooks. Top with bean sprouts, chopped cilantro, lime juice, sliced jalapeños etc.