Step 1

Cover chicken pieces (including carcass) with cold water by 2 inches. Bring to a boil over high heat. Reduce to a simmer and cook until center of chicken breasts registers 145°F on an instant-read thermometer, about 15 minutes. Remove chicken breasts. Continue cooking until legs are completely tender, about 45 minutes longer, adding more water as necessary to keep chicken submerged. Transfer legs to bowl with chicken breasts and allow to cool. Discard carcass.

Step 2

While broth cooks, combine hot chilies, coriander, Sichuan peppercorn, long pepper, cloves, star anise, mace, cinnamon, cardamom, and black pepper in wok. Heat over medium heat, stirring and tossing constantly, until toasted and fragrant, about 2 minutes. Transfer to a mortar and pestle or a spice grinder and grind into a fine powder. Wipe out wok. Add shrimp paste to spice mix and blend with a fork until homogenous.

Step 3

When chicken is cooked, add galangal and lemongrass to broth and simmer for 15 minutes. Strain broth through a fine mesh strainer and set aside. Pick chicken meat into bite-sized pieces and discard bones.

Step 4

Heat oil in the now-empty wok over high heat until shimmering. Add mushrooms and cook, stirring occasionally, until lightly browned, about 8 minutes. Add shallots and spice mix and cook, stirring constantly, until fragrant, about 30 seconds. Add strained broth and chicken pieces. Bring to a simmer, stir in cilantro, and season to taste with fish sauce and salt. Serve immediately.