Mix all the marinade ingredients. Place the pork belly in a dish and pour over the marinade. Set aside in the fridge for a few hours, preferably overnight.
Cooking in convection oven:
When you are ready to cook, remove the pork belly from the marinade, pat dry with a paper towel then rub the fat side with freshly ground salt. Crackling is all about skin and fat. The meat underneath is a question of taste. Pork belly is the safest choice, as the meat is marbled with fat and is harder to overcook.
Place the pork on the wire rack in the convection oven. Try to get the pork as close to the heating cells of the oven as possible. Turn the oven to 220 degrees C to get the crackling going. When you are satisfied with the crackling, turn down the oven to 180 degrees C and leave for 1 hour.
Remove from the convection oven, cut in slices and place it back to the rack in the convectional oven if you like it more grilled. (Optional)