Step 1Use a sharp knife to peel the skin from the pork belly: Cut a corner free, then grab it firmly and pull away, cutting with the knife while keeping the sharp edge of the blade against the tough skin. When the skin has been removed, cut the pork belly into roughly 3-by-1-inch pieces.
Step 2In a spice grinder or coffee mill, grind the peppercorns, cinnamon, cloves, allspice, bay leaves and salt to a powder. Sprinkle the mixture over the meat, add the thyme and mix well. Add the wine and mix again. Cover tightly and refrigerate overnight.
Step 3The next day, heat the oven to 250 degrees. Remove the pork pieces from the marinade and pat them dry with a paper towel. Place them in a Dutch oven in as close to an even level as possible. Cover completely with olive oil. Bring to a slow bubble on top of the stove over medium heat, then transfer to the oven and let it cook, uncovered, until the meat is quite tender, about 2 1/2 hours.
Step 4Remove from the oven and let the meat cool in the fat. When the meat is cool, transfer it to storage containers and pour the fat over top, seal tightly and refrigerate. The meat should be completely submerged. (The confit can be used immediately, but it's better if it's refrigerated for 24 hours.)
Step 5To cook, remove the meat from the container along with a little of the fat. Fry over medium-high heat, turning to brown all sides. When the meat is well browned and heated through, serve immediately.