Wipe the pork belly off with paper towels and place it on a sheetpan, skin side up. Make sure the skin is very dry and store it in the fridge overnight. 

When you are ready to cook, preheat your oven to 300°F (148°C). 

Remove the pork belly from the fridge and dry the skin very well with paper towels. Rub the olive oil all over the surface of the pork belly, and then coat all sides with your seasoning blend. 

Place the pork belly on a wire rack placed in a sheet pan or baking dish, skin side up, and cook for 2.5 to 3 hours or until the internal temperature reaches 190°F.

Remove the pork belly from the oven and raise the heat in the oven to 500 degrees F (260°C).

Place the pork belly back in the oven for an additional 25 to 30 minutes. This is meant to crisp up the skin. You can also crisp up the skin by using the oven broiler as well, but be very careful because the exterior will burn quickly if you're not paying attention.  

Remove the pork belly from the oven and allow it to cool for at least 30 minutes before slicing. If you want thinner slices, you can cool the pork belly in the refrigerator for 3 or 4 hours until the meat is firmer. 

If you're using this pork belly in a sandwich, I like to sear the slices until they start to brown a little in a skillet or pan. This will warm the meat and create more texture on each slice.