- 2 tbsp sea salt flakes
- 2 tbsp dark brown sugar
- 1 tsp black peppercorns
- 4 garlic cloves, lightly crushed
- 2 bay leaves
- 2 tbsp yellow mustard seeds, 1 tbsp soaked in cold water overnight
- 4 sprigs fresh thyme
- 4 sprigs fresh flatleaf parsley
- 500ml/18fl oz beer, preferably a good-quality ale
- 1 x 1-1.2kg/2lb 4oz-2lb 10oz six-rib pork loin rack, French-trimmed (ask your butcher to do this for you)
- 75g/2½oz unsalted butter
- 100g/3½oz brioche, roughly torn
- 1 tsp English mustard powder
- 1 tbsp brown mustard seeds, soaked in water overnight
- 700g/1lb 9oz Swiss chard, trimmed, chopped into 2cm/¾in slices
- 2 large potatoes, peeled and cut into 1.5cm/½in pieces
- 1 onion, sliced
- 50g/1¾oz unsalted butter
- 50g/1¾oz plain flour
- 400ml/14fl oz full-fat milk
- 200ml/7fl oz chicken stock
- 100g/3½oz Gruyère, grated
- salt and freshly ground black pepper
- For the pork, pour 100ml/3½fl oz cold water into a large saucepan. Add the sea salt flakes and sugar and heat over a low heat until dissolved, stirring well. Remove the pan from the heat and add 400ml/14fl oz cold water, the peppercorns, garlic, bay leaves, unsoaked yellow mustard seeds, thyme, parsley and beer.
- If the pork loin rack fits into the pan, add it to the pan. Otherwise, place the pork loin rack in a large bowl and pour over the liquid. Cover and chill in the fridge for 24 hours to marinate, turning the pork occasionally.
- When the pork has marinated, preheat the oven to 200C/180C Fan/Gas 6.
- Remove the pork from the marinade and pat dry with kitchen paper.
- Heat 50g/1¾oz of the butter in a large frying pan over a medium heat. When the butter is foaming, add the pork loin rack and fry for a few seconds on all sides, or until lightly browned all over. Transfer the pork loin rack to a roasting tray and roast in the oven for 15 minutes.
- Meanwhile, blend the brioche, English mustard powder and soaked yellow and brown mustard seeds to a paste in a food processor with the remaining butter. Season, to taste, with salt and freshly ground black pepper, then set aside.
- For the gratin, arrange half of the Swiss chard in a layer at the bottom of an ovenproof dish and top with half the potatoes. Sprinkle over the onion, then top with layers of the remaining Swiss chard and potatoes.
- Melt the butter in a saucepan over a medium heat. Add the flour and whisk well to combine with the melted butter. Continue to cook for 1-2 minutes, whisking regularly, then gradually pour in the milk, whisking continuously, until all of the milk has been incorporated and the mixture has thickened to a smooth sauce.
- Whisk in the stock and half of the Gruyère and stir until melted. Season, to taste, with salt and freshly ground black pepper.
- Pour the sauce all over the chard and potatoes. Sprinkle over the remaining Gruyère.
- After the pork has been cooking for 15 minutes, remove it from the oven and decrease the temperature to 180C/160C Fan/Gas 4.
- Spread the brioche and mustard paste all over the top of the pork loin rack in a thick layer, then return the pork to the oven, along with the Swiss-chard gratin. Cook both for a further 45 minutes, or until the pork is cooked to your liking and the crumb has crisped up and turned golden-brown, and the Swiss-chard gratin is bubbling and golden-brown.
- When the pork is cooked to your liking, set it aside to rest for 15 minutes (keep warm). Continue cooking the Swiss-chard gratin for a further 15 minutes, if necessary; otherwise, keep warm.
- To serve, carve the pork loin rack into six chops. Place one onto each serving plate and spoon the Swiss-chard gratin alongside.