Place a 2.5kg pork belly in the fridge uncovered overnight.
Next day, wrap foil so it covers just the meat, leaving skin exposed.
Brush with olive oil, season with salt, and roast at 140°C for 2½ hours.
In a casserole pot, combine 2 quartered fennel bulbs, 6 halved shallots, 1 halved garlic bulb, 2 apples (cut into sixths), thyme, fennel seeds, salt, pepper, and olive oil.
Roast the vegetables for 1 hour in the same oven.
Pour pork juices into the veg.
Roast both together at 240°C for 30-40 mins to crisp the skin.
Remove the pork and rest uncovered.
Deglaze the casserole with 1-2 bottles cider, boil, strain, and reduce until glossy.
Serve the veg in a dish, spoon over the cider gravy, and slice the pork to serve on top.
