The lamb: Trim lamb loins, setting the fat aside, toss the silverskin. Cut into serving sections. Season with salt and pepper, lightly coat with olive oil, and vacuum seal in bags, side by side, ready for sous vide cooking. Pull out your trusty Nomiku (or other sous vide circulator), and cook the lamb for two hours at 56.5°C/134°F (medium rare), remove from the water bath and set aside until ready to use (you can even cook and refrigerate these the day before). For service, remove the loin sections from their vacuum pouches, season again with salt and pepper and sear the outside in olive oil and butter, just enough to get a nice crust on the surface and rewarm, but not continue cooking, the inside.
The potatoes: Peel and boil potatoes in salted water. Meanwhile, take all the lamb fat scraps and render them down in a pot, over low heat, until you’ve gotten as much of the fat liquid as you can – this actually takes about an hour, so perhaps “meanwhile” isn’t the approach – do this earlier. Mash the potatoes with the lamb fat (in place of the usual butter), milk, salt and white pepper to taste.
The sauce: Rehydrate a few sun-dried tomatoes in just enough hot water to cover. Place in blender along with a fresh tomato, some pitted black olives, malagueta (aka piri-piri) chilis, plain yogurt, and a splash of sesame oil. Puree at high speed, adding in just a little xanthan gum to thicken it. Adjust seasoning – salt and black pepper.
The vegetable pickle: Thinly slice radishes, red onion, green olives, and quarter some cherry tomatoes. Place in a large bowl. Bring a cup of rice vinegar to simmer with a couple of tablespoons of sugar, one of salt, and some coriander seeds and white peppercorns. Let simmer for five minutes to infuse well, then pour over the vegetables, making sure they’re covered. Every half hour or so, mix them up a bit, they’ll take around four hours to be pickled just perfectly. Add a handful of chopped parsley just before using. I like to warm this up slightly, though not get it really hot.
Garnish with sauteed or grilled baby leeks.