Begin by heating a tablespoon of oil in a large pot over medium-high heat. Halve the onion and ginger, then add them to the pot, allowing them to char until blackened, which should take about 4 minutes.

Once the onion and ginger are charred, add 8 cups of water to the pot along with the chicken thighs, fish sauce, sugar, and spices. Bring the mixture to a gentle simmer.

Reduce the heat to maintain a very gentle simmer and partially cover the pot. Allow the broth to simmer for 1.5 hours, skimming any foam that rises to the top periodically.

After simmering, carefully remove the chicken thighs from the broth. Using a fine-mesh strainer, strain the broth into a clean pot to remove all solids and spices.

With the strained broth ready, add salt to taste and keep it warm over low heat.

Prepare the rice noodles according to the package instructions, ensuring they are perfectly tender.

In serving bowls, layer the cooked noodles, shredded chicken from earlier, and ladle the hot broth over the ingredients.

Finally, top each bowl with fresh garnishes such as bean sprouts, Thai basil, coriander, and lime wedges. You can also drizzle hoisin sauce and sriracha.