Adam Byatt’s herb-crusted lamb rack with romesco sauce

Method

1. Begin by making the herb crust. Put all the ingredients in a large bowl and mix with a wooden spoon until combined. Put a large piece of baking paper on a work surface and transfer the mixture onto it. Put another piece of baking paper on top, then roll the mixture out to 4-5mm thick square or rectangle. Cut into quarters, put 1 quarter in the fridge to firm up, then wrap the other 3 portions separately and put in the freezer for another day.
2. To make the romesco, heat the grill to medium. Put the peppers on a baking  tray and grill for about 20 minutes, turning occasionally, until blackened all over. Transfer to a bowl, cover and leave to steam for 5 minutes until cool enough to handle. Peel off the blackened skin, remove the seeds and stalks and cut into quarters.
3. Heat the oven to 180°C/160°C fan/gas 4. While you wait, add a dash of olive oil to a wide frying pan over a low-medium heat and fry the hazelnuts for about 5 minutes, stirring regularly, until golden. Set aside.
4. Add the tomatoes, garlic, a dash of olive oil and a big pinch of salt to a baking dish. Mix together, then roast for 15 minutes until the tomatoes have cooked down. Transfer the mixture to a blender (leave the oven on) with the peppers and bread, whizz into a paste, then add the shallot, vinegar, 100g olive oil and the hazelnuts. Pulse into a coarse sauce, then set aside at room temperature (see Make-ahead).
5. Add another dash of olive oil to a large ovenproof frying or sauté pan. Season the lamb rack liberally with salt, then put it fat-side down in the pan. Put the pan over a low-medium heat and gradually bring it up to temperature, rendering the fat slowly for 8-10 minutes.
6. Turn the rack over and sear the meat side, then lift it out and add the thick discs of onion to the pan to create a trivet. Put the lamb rack, fat-side up, on the onions, then brush the fat with the extra mustard. Take the herb crust out of the fridge, remove the bottom sheet of baking paper, then lay the herb crust on top of the fat and remove the top layer of baking paper. Trim the crust down to the same size as the lamb, then transfer the pan to the oven. Roast for 6-10 minutes; if you have a probe thermometer it should read 50-54°C in the centre of the meat. Take the lamb out and leave to rest for 10 minutes.
7. To serve, spread a generous amount of romesco sauce on a platter. Carefully carve the lamb rack, cutting between each bone and trying not to disturb the herb crust too much. Arrange the cutlets on top of the sauce, then drizzle over a little more olive oil.