Very lightly adapted from Charles Phan's Vietnamese Home Cooking (Ten Speed Press, 2012). (I've left out a black cardamom pod; of course, if you happen to have such, throw it in with the other spices.) —Nicholas Day
light soy sauce (if you only have standard soy sauce, that's fine)
light brown sugar
pork shoulder, cut in two equal pieces
Toast the cinnamon, star anise, and cloves in a dry frying pan over medium heat for 30 seconds, or until fragrant. Place in a large pot along with the ginger, five-spice powder, fish sauce, soy sauce, and brown sugar. Add 7 cups of water. (Yes, seven cups.) Bring to a boil, stirring occasionally. Reduce to a simmer.
With the liquid at a low simmer, add the pork shoulder. Cook for 20 minutes. Then turn off the heat and let the pork sit in the pot for another 30 minutes. Remove the pork and let cool; slice thinly. Serve with rice, soft-boiled eggs, and plenty of sauce.
To preserve the lo soi (the flavored liquid): skim off the scum and fat and strain into a large container. Then refrigerate or freeze until next use. Before using it again, add fresh spices (the first four ingredients above); tinker with the soy sauce or sugar as needed. If you refrigerate the lo soi and do not use it for a month, return it to the stove and boil for five minutes, then refrigerate again; it should keep up to a year.