Rinse the oxtail with salt, then place it in a pot with 8 1/2 cups water (2 liters). Add the chicken bones to the pot to create a sweet broth. Char one onion and the ginger over a grill or open flame, then peel and rinse them before adding to the pot.

When the broth comes to a boil, skim off any foam and fat to keep the broth clear. Add the spice mix and chicken to the pot. Simmer until the oxtail is tender, adding more water as needed since some will evaporate during cooking. Remove the chicken, let it cool, then cut it into bite-sized pieces. Season the broth to taste. Slice the remaining onion, green onions, lime, and chili, and arrange them on a plate. Soak or briefly cook the pho noodles until soft.

Place the pho noodles in bowls, top with chicken, oxtail, and onions, then ladle hot broth over everything. Sprinkle with black pepper and enjoy your bowl of Northern-style pho while it’s still hot and flavorful.