1. Preheat oven to moderately hot 210 C. Spray lamb with olive oil and rub with 1/4 cup spice. Marinate for 10 min. Cut vegies into 2cm chunks, toss with 2 tablespoons of olive oil and season with salt and pepper. Spread on a baking tray lined with non-stick baking paper. Roast for 20 min.
2. Combine remaining spice and yoghurt. Barbecue or grill lamb to your liking. Remove lamb from heat and rest 5 min before slicing into 1cm strips. Serve on a bed of couscous with roast vegies and a dollop of prepared yoghurt.