1. Prepare the Aromatics:

1. Char the onion and ginger over an open flame, grill, or in a dry skillet until slightly blackened. This enhances their flavor.

2. Make the Broth:

1. In a large pot, combine the stock, water, charred onion and ginger, cinnamon stick, star anise, cloves, and coriander seeds.
2. Bring to a boil, then reduce heat and simmer for 30–45 minutes.
3. Add fish sauce, sugar, and salt to taste. Strain the broth to remove the solids and keep warm.

3. Prepare the Noodles:

1. Cook the rice noodles according to package instructions. Drain and set aside.

4. Prepare the Protein:

1. If using raw beef or chicken, slice it thinly against the grain. The hot broth will cook the meat in the bowl.
2. For tofu or pre-cooked protein, warm them briefly in the broth.

5. Assemble the Soup:

1. Divide the cooked noodles among serving bowls.
2. Top with your choice of protein, then ladle the hot broth over the noodles and meat.
3. Add bean sprouts, fresh herbs, and chili slices as desired.

6. Serve:

1. Serve with lime wedges, hoisin sauce, and sriracha on the side. Let each person customize their bowl to taste.