Lemon, garlic and rosemary leg of lamb with mint sauce

Method

1. Put the butterflied lamb skin-side up on a chopping board and trim off any particularly thick areas of fat so it’s as even as possible, then use a sharp knife to score a 2cm diamond cross-hatch through the fat, ensuring you don’t cut into the meat below. Turn it over and make many deep cuts in the meat, around 1cm wide at regular intervals all over the lamb. Rub the lamb all over with the lemon zest. Poke slivers of garlic and a few rosemary leaves into each hole, then season all over with salt and pepper. If you have time to marinate, put the lamb in a container in the fridge overnight.
2. Heat the oven to 200ºC/180ºC fan/gas 6. It’s likely the lamb won’t fit in your frying pan, so you can cut it in half; if one half is thicker than the other, cut it there so you can tweak cooking times if needed. Put a large frying pan over a medium heat, add 1 tsp oil and lay the lamb skin-side down in the pan, then turn up the heat to medium-high. Cook until the fat has rendered into the pan and the skin is crisp and golden (around 5 minutes). Flip with tongs to briefly brown the other side, then transfer to an oven tray, skin-side up. Repeat for the other lamb half (or use 2 pans and do both halves at the same time).
3. Put the lamb in the oven for 20 minutes or until a meat thermometer pushed into the thickest part of each piece reads 60ºC (it will take a little longer if the meat is thicker than 4cm). When each piece reaches the correct temperature, leave to rest in a warm place for around 10 minutes before carving.
4. Make the mint sauce while the meat rests. Mix the boiling water and soft  brown/demerara sugar together until the sugar has dissolved, then stir in the vinegar and chopped mint and season with salt and pepper. Taste, adding more sugar or vinegar if required, then serve alongside the lamb.