Cook the family a Sunday roast to remember with this premium cut of lamb, crusted with citrus and herbs.
For the brown lamb stock, preheat the oven to 200C/180C Fan/Gas 6. Place the lamb bones in a roasting tin and roast into the oven for 20-30 minutes, or until the bones have darkened and the fat and marrow from inside the bones has melted.
Drain the fat from the roasting tray and reserve. Transfer the bones to a large saucepan. Wipe the roasting tray clean with a piece of kitchen paper.
Place the roasting tray over a medium heat, add a splash of water and bring to the boil, scraping up any burned bits from the bottom of the tray using a wooden spoon. Pour the liquid into the saucepan containing the bones, then add 500ml/18fl oz water, the bay leaves, rosemary and chicken stock. Bring the mixture to the boil, then reduce the heat until the mixture is simmering gently and continue to simmer for 2 hours.
Strain the stock through a fine sieve into a bowl. Cover the bowl and set aside to cool, then chill in the fridge overnight. During this time the fat will rise to the top of the stock and solidify.
The next day, remove the solid layer of fat from the surface of the chilled stock. Pour the stock into a saucepan and bring to the boil. Reduce the heat until the stock is simmering, then simmer until the volume of liquid has reduced by about 100ml/3½fl oz and the stock has thickened. Keep warm.
For the aubergine purée, pierce the aubergine all over with a sharp knife, then transfer to a plate and cover with cling film. Microwave on full power for 8-10 minutes, or until deflated and very soft in the middle. Alternatively, place the pierced aubergine on a baking tray and bake in the oven set to 200C/180C Fan/Gas 6 for 45-60 minutes.
Set the aubergine aside to cool, then cut in half lengthways, scoop out the flesh and mash well. Drain the aubergine flesh in a colander for an hour.
Heat the oil in a saucepan over a medium heat, then add the drained aubergine, dill, mint, yoghurt, lemon zest and lemon juice and stir well until warmed through. Season, to taste, with salt and freshly ground black pepper. Keep warm.
For the crusted lamb, dry-fry the cardamom pods over a medium heat for 30 seconds, or until fragrant. Set aside on a plate.
Add a little oil to the pan, then fry the lamb rack for a few seconds on all sides until browned all over. Place the lamb skin-side down and continue to fry until the fat melts.
Blend the sourdough, mint, toasted cardamom pods, and English mustard to a rough purée in a food processor.
Transfer the lamb rack to a roasting tray and brush the meat with a little English mustard. Spread a tablespoon of the mint mixture onto the fatty side of the lamb rack. Roast in the oven for 12-15 minutes (for medium-rare), or until cooked to your liking. Remove the lamb from the oven and set aside to rest for 10 minutes.
Meanwhile, for the gravy, pour the juices from the roasting tray into a saucepan, then add the reduced lamb stock, red wine vinegar and sugar and stir well until the sugar has dissolved. Bring the mixture to the boil, then reduce the heat and simmer for 10-15 minutes, or until the volume of liquid has reduced enough to form a thick gravy that coats the back of a spoon. Just before serving, stir through the chopped mint.
To serve, carve the lamb rack into cutlets and divide them equally between two serving plates. Spoon the aubergine purée alongside, then drizzle over the gravy.
Tom Kerridge makes 1 litre/1¾ pints of brown lamb stock, which is not all used in the recipe. The remaining stock can be frozen in an ice cube tray for future use. Alternatively, use ready-made lamb or beef stock.
Cadet de Ka 2010 Bekaa Valley, Lebanon, Bodegas Sarria San Antolin 2004 Reserva Navarra Spain or Cortes de Cima 2011 Alentejo.
