Place the loin of pork in a large roasting tin. Pat the skin with kitchen roll and ensure it is completely dry. Ideally leave it to dry overnight.
Rub 1 tablespoon of sea salt into the skin. Cover and leave at room temperature for 1 hour. Dry the skin again with kitchen paper and rub in the remaining 1 tbsp of salt.
Pre-heat your oven to 240ºC/ 220ºC fan/ gas mark 9.
Place the pork in the pre-heated oven and roast for 45 minutes. Remove from the oven and add the sage leaves and lemon zest.
Turn the oven down to 180ºC/ 160ºC fan/ gas mark 4 and roast for a further 1 hour. 15 minutes before the end of the cooking time, take the join out of the oven and pour over the melted Lurpak®, return to the oven for the final 15 minutes.
Remove the pork from the oven, check that any juices are running clear, cover loosely and allow to rest for at least 20 minutes. Serve with the red cabbage.
To make your braised red cabbage:
Place all of the ingredients into a large saucepan, bring to the boil and then reduce the heat to a simmer and cook for about 30 minutes until the cabbage has softened. Right at the end add in the cold Lurpak® and mix until melted and the cabbage is glossy.