- Step 1
In a small saucepan, heat 1 tablespoon of water over medium heat until hot, and then add the saffron and heat for 1 minute to bloom the saffron. Add the olive oil, cumin, 1 teaspoon of salt and 1/4 teaspoon of pepper and continue cooking the mixture until it is warm. If using turmeric instead of saffron, simply heat the turmeric in the olive oil mixture until warm.
- Step 2
Pour half of the saffron-oil mixture into a small bowl and mix in the lemon juice. Cover and refrigerate the lemon-saffron mixture.
- Step 3
Transfer the remaining saffron-oil mixture to a large bowl and set aside to cool to room temperature. Whisk in the yoghurt, garlic and lemon zest. Add the lamb to the yoghurt marinade and turn to coat. Cover and refrigerate overnight.
- Step 4
Prepare a barbecue for medium heat. Remove the lemon-saffron mixture from the refrigerator and set it aside to come to room temperature.
- Step 5
Wipe off any excess marinade from the lamb. Season generously with the salt and pepper. Barbecue the lamb, rotating as needed, for about 16 minutes per side, or until an instant-read meat thermometer registers 60°C when inserted into the thickest part of the lamb. Transfer the lamb to a carving board to rest for 10 minutes.
- Step 6
Cut the lamb across the grain into very thin slices and transfer it to a platter. Mix any accumulated lamb juices into the lemon-saffron mixture and pour it over the lamb or serve it alongside.
Make-Ahead: The lamb can marinate up to 2 days ahead. Keep refrigerated.