1. Mix together the brandy or whiskey with the garlic, salt, pepper, juniper, and allspice berries with the pork cubes in a bowl. Cover and refrigerate overnight.
2. In a large saucepan (that has a lid) or a medium-sized casserole, heat the pork belly pieces with 1/3 cup (80ml) water over low heat. Cook gently for 15 minutes, stirring occasionally, encouraging the pork pieces to give up their fat. If the water evaporates, add a little more to help the fat render.
3. Preheat the oven to 250ºF (120ºC).
4. Add the macerated pork and any liquid to the pan along with the thyme. Cook, stirring frequently, for another 15 minutes, until the pieces of pork are cooked on the outside. Cover the pan and put it in the oven.
5. Lift the lid after 1 1/2 hours of cooking. Press on the chunks of fat with a fork to release more of their fat and encourage them to break down. Add the wine, replace the lid, and bake the pork for another 1 to 2 hours, until the pork is very soft.
6. Remove the pork from the oven. Pick out the thyme branches and discard. (The original recipe said at this point to drain the pork through a sieve, over a bowl, to collect the juices, but mine didn’t have enough to warrant that. If yours does, see headnote for more information on that.)
Press on any visible chunks of fat to get the fat out of them, then remove them from the pan and discard them.
7. Pour most of the fat out of the pan into a small bowl and reserve. Scrape the meat chunks, and any pan fat, juices and brown bits, into the bowl of a stand mixer. The spices should all be very soft and dissolved, so it’s not a problem to include them.
8. Mix the meat on low-to-medium speed with the paddle attachment until well-mashed. (You can also make this by hand, mashing the meat with a fork.) The mixture should resemble dry tuna salad. Add enough of the reserved liquefied fat to make it juicy and moist. I ended up adding about 3 tablespoons, but it’ll probably need between 2 and 4 tablespoons. The more fat you add, the richer and creamier it’ll be.