Pre heat oven to 200°C. Mix the lamb rub spices together with olive oil and rub all over the surface of the lamb. Pierce the lamb with small incisions randomly with a small knife and stuff with whole garlic cloves and rosemary sprigs.
Bake the lamb for 30 mins until browned. Once browned, wrap the shoulder in baking paper then foil. Reduce the oven heat to 160°C and cook for a further 2 hours until very tender.
Wash and trim the carrots and mix in tahini, cumin, honey, olive oil and season with salt and pepper. Keep to one side and bake at 160°C for the last 20 mins with the lamb.
Rest the lamb for 10 mins before carving. Serve with yoghurt mixed with lemon juice.