This is an adaptation of a recipe intended for a whole, butterflied leg of lamb. Both are excellent, but you'll want to add an extra tsp of salt if you're using this marinade on a whole leg.
Cut leg of lamb into 1 - 2 inch cubes.
Combine ingredients except yoghurt and saffron. Rub mixture over lamb pieces.
Soak saffron strands in 2tbsp hot water for ten minutes, then mix saffron, water, and yoghurt.
Pour yoghurt mix over lamb. Marinate over night.
Thread the meat onto metal skewers.
I like lamb that is medium rare but nicely charred on the outside, so I prefer a very hot BBQ, where I cook the skewers for about 3 minutes and then flip them and repeat on the opposite side. Wide metal skewers help ensure that the middle gets some heat, and keep the meat from spinning when you try to turn them over.