For pork belly, place the pork belly into a large pan over a medium heat and cover with water. Bring to the boil, then drain off the water and return the pork belly to the pan.
Cover with water again and add the carrot, onion, garlic, celery, thyme, salt and peppercorns. Bring to a boil, then reduce the heat and simmer for two hours.
Carefully remove the pork from the pan and place onto a large plate. Place a large, clean tray on top, then place a couple of cans on top of the tray to apply weight. Transfer to the fridge and leave for one hour, or until cold and pressed flat.
Remove the pork from the fridge, remove the tray and weights and place onto a chopping board. Cut the pork into 1.5cm/½ thick slices.
Heat a frying pan and add the vegetable oil. Season the pork slices with salt and freshly ground black pepper and fry in the hot oil until crisp and golden all over.
For the caramelised onions, heat a clean frying pan add the butter, onions, sugar and thyme. Fry over a gentle heat for 5-10 minutes, until the onions are just tender.
Turn the heat up and fry the onions until just becoming golden-brown.
Add the balsamic vinegar and reduce until very little liquid remains, then season with salt and freshly ground black pepper.
For the balsamic sauce, heat a clean frying pan and add the butter and shallots. Fry the shallots for 3-4 minutes, or until softened, but not coloured.
Add the balsamic vinegar and boil to reduce the volume by two thirds.
Add the stock and reduce again by two thirds, until a thick sauce forms, then season with salt and freshly ground black pepper.
For the scallops and squid, season the scallops and squid with salt and black pepper.
Heat a frying pan and add the vegetable oil, scallops and squid. Fry the scallops and squid for 2-3 minutes, or until completely cooked through, turning the scallops over halfway through.
To serve, place a few slices of pork belly in the centre of each plate and top with a spoonful of caramelised onions. Place three scallop pieces on top of each, then top with the squid. Spoon the shallot sauce around the plate and serve.