Begin your marinade by placing the spices, yogurt, garlic, lemon juice, zest, salt and pepper in a large resealable bag. Add in the racks of lamb and massage the mix into the racks of lamb ensuring it covers all the lamb. Reseal the bag and leave it to marinate for minimum 4 hours preferably overnight in the fridge.
Once marinaded, heat a heavy based frying pan, add a splash of oil and brown the lamb for 1 to 2 minutes on either end of the rack. Leave the skin uncooked as that is where the crumbs will stick to.
Preheat the oven to 200°C.
For the Crumb, add the dry ingredients, olive oil, chopped herbs to a large bowl and mix together. Turn the racks so that they are fat-side up, and brush with mustard.
Pack on the herb crust gently with your hands, drizzle with a bit of oil and place on a large baking tray in the preheated oven to roast for 25 minutes until the crust is golden and the lamb is cooked. This will produce lamb that is pink in the middle but cooked all the way through.
For the Yogurt Dressing, simply add all the ingredients into a bowl and mix thoroughly cover and allow the flavours to develop
Remove and allow the lamb to rest for 10 minutes. The lamb tastes great served with boiled baby potatoes, couscous or a tasty salad of cucumber, tomato, red onion, mint and pomegranate.