Choose a new cookbook worth up to £28 when you subscribe to our magazine.
Tip the rosemary and garlic into a mortar along with the fennel seeds, olive oil and a good pinch of salt. Pound everything together with a pestle until you get a rough paste. Unfold the pork loin, spread the herb mixture all over the cut side, then fold the loin back over. You need to keep the loin together during cooking, so tie pieces of string around it at 2cm intervals. Tuck any leftover rosemary sprigs under the string.
Heat oven to 220C/fan 200C/gas 7. Lightly oil a baking tray and place the pork on top, sprinkling a little salt over the skin. Cook in the oven for 20 mins until crisp and browned all over. Reduce oven to 190C/fan 170C/ gas 5 and cook for 45 mins per kg more, which will be just under 2 hrs for this amount of meat. When ready, take the pork out of the oven and cover tightly with tin foil. Leave for at least 15 mins before eating, or leave to cool and keep in the fridge for up to 2 days. To serve, loosen the crackling, then carve the pork into thick slices, handing out pieces of crackling if people wish.