Combine the sugar, salt and black pepper and mix well. You will likely have too much so don't feel like you have to use all of it. You want to coat liberally. Not pack it in the cure mix. Don't use table salt. Diamond crystal kosher salt. If you want to try it with table salt please roll way back on the amount of salt you use. It's tested with diamond crystal. It works with diamond crystal.
Remove the skin from the pork belly. You can get your butcher to do this for you. If you want to do it yourself it's not that hard if you have a good knife. Run the blade along the skin, pulling the flap of skin up as you go along. If you screw up don't worry. Just try again. It's not like it has to be perfect. It's a pork belly...
Pull out a cookie sheet. Put the pork on the cookie sheet and coat the pork belly liberally with the sugar, salt and black pepper mixture.
Refrigerate the pork belly, uncovered for 12 hours. Try not to go less than 10 hours. Don't go much over 14. A long cure is not what you are looking for here.
Pre-heat your oven to 290F.
Remove the pork from the fridge, brush any remaining cure from the surface (or give it a quick rinse) and place it in a baking pan large enough to hold it comfortably. If you don't have one, use your cookie sheet. Cover with foil and place in the oven.
Cook to an internal temperature of 190F. I can't tell you how long this will take because I don't know how thick your pork belly is. Maybe 4 hours. But start checking after two hours. This is like BBQ. It's done when it's done.
Remove the pork from the oven and let rest 10-15 minutes. Slice and serve.
To re-heat, steam slices if you want it meltingly tender. Pan-fry slices if you want a bit of crust. All good...