small bunch fresh mint leaves, cut into thin strips
Using a sharp knife, cut three slashes in the top of the lamb and two on the underside.
Line a large baking tray with baking paper. Mix together all the marinade ingredients (you only need half the lime juice) in a bowl and season generously with salt and pepper. Transfer to a blender and blitz to form a smooth paste.
Place the lamb on the baking tray and massage in the paste – especially into the slashes and around the bone areas. Cover and place in the fridge for at least 1 hour, or preferably overnight.
Preheat the oven 220C/200C Fan/Gas 7.
Put the lamb in the oven and immediately reduce the temperature to 190C/170C Fan/Gas 5. Roast for 1 hour. (Alternatively, cover the lamb with kitchen foil and slow-cook at 180C/160C Fan/Gas 4 for 4 hours.)
Meanwhile, to make the peppers, place a large frying pan over a high heat. Add the cumin and enough garlic oil to cover the base of the pan. Add the padron peppers and stir-fry for 2 minutes, ensuring they are coated in the cumin seeds and oil. Cover with a lid and shake the pan. Cook for 1 minute, or until the skins brown and blister. Transfer to a serving plate.
Fry the breadcrumbs in the pan over a medium–high heat for 30 seconds, or until golden brown and crispy. Remove from the heat and add the sumac and lemon zest, then scatter it over the peppers.
Put the peaches, red onion, chilli flakes, lemon juice and a good drizzle of olive oil in a mixing bowl. Season generously with salt and pepper and mix well. Transfer to a serving dish and scatter over the feta and mint.
Cover the lamb loosely with kitchen foil and allow to rest for 10 minutes before serving.
Carve the lamb into thick slices and serve alongside the peppers and salad.