Toast the spices – Place the cinnamon, coriander, cloves, and star anise in a pan and set the heat to medium heat. Toast until you smell the fragrance of the spices, about 2 minutes, and set aside.
Char the aromatics – Cut the ginger and onions so that it has a flat surface area and sauté in a pan until it is charred.
Make the stock – Gather the stew ingredients. In a large pot, add about 3 cups of water, along with the spices put in a cheesecloth bag if you have it, the chicken, and the charred aromatics. Add in some of the fish sauce, sugar, and salt to season the chicken as it cooks. Bring the stock to a boil, then lower to a light simmer so as to not overcook the chicken. Cook for about 1 hour.
Prepare the noodles – While the stock is cooking, cut the garnishes in preparation for putting together the noodle bowl. Slice the chili peppers, limes, and scallions. And cook the noodles according to the package directions.
Adjust the stock – Once the stock has reached its cooking time, have a taste and adjust the seasoning accordingly. Traditionally, it is adjusted with fish sauce and sugar.
Serve and enjoy – In a bowl, add the noodles, add the stew, garnish with cilantro, scallions, chili, and lime, and enjoy! Serve it with a side of hoisin sauce if desired.