1. Remove your joint from your fridge for an hour or so before cooking to allow it to warm at room temperature.
2. Pre-heat your oven to 220C. Whilst your oven is heating up, wash your potatoes and carrots, but leave the skin on. Slice your potatoes into four roughly the same thickness as your carrots to ensure they roast at the same speed. Peel your onions and cut into four.
3. Place all of your vegetables in a deep bottomed oven tray and drizzle with oil. Pull the fresh thyme leaves away from the stem and scatter over your vegetables. Place your loin of pork on top of your bed of vegetables and season. Rub a generous amount of sea salt over the skin of the joint to ensure you get the very crunchiest of crackling.
4. Roast for 2 hours or until you get a core temperature of 65C.
5. Remove from your oven tray and leave to rest under a few sheets of loose foil for at least 20 minutes.
6. While your meat rests, pour any excess liquid from your tray into a saucepan and pop your tray of veggies back into your oven.
7. Place your pan of juices on your hob and add your pouch of broth. Simmer until it reduces to a rich jus.
8. Carve your pork loin between the bones to serve.