Shred off all the chicken/meat off your rotisserie chicken and set the chicken aside.
Toast all of your spices listed under PHO SPICE on a dry skillet. Add your spice into a spice bag or cheesecloth and tie it tightly.
In the same skillet, toast your onions and ginger until it gets charred.
Toss everything into a pot: chicken carcass + skin, charred onion and ginger, rock sugar, chicken drippings and 4-5 quarts water. Bring this to a boil and simmer for at least 30 minutes but no longer than 2 hours. If you plan to simmer for more than 30 mins, remove your spice bag.
Once you are done simmering, remove everything inside: bones, onion, ginger, etc.
Season broth to preference using: chicken bouillon, fish sauce, salt, sugar and/or MSG.
Assemble a bowl of pho using: pho noodles, shredded chicken, chopped scallion, chopped cilantro, thinly sliced onions, black pepper, sriracha, hoisin sauce, chili oil and any other condiments you prefer.
