Place the cumin and coriander seeds in a mortar and grind with a pestle to a coarse powder. Transfer to a bowl and stir in the garlic, yogurt, chilli, paprika, oil and lemon juice. Add the lamb chops and rub in the marinade.
Marinate in the fridge for at least two hours.
Heat a griddle pan or barbecue until medium-hot.
Season the lamb with a little salt and grill for 2-3 minutes on each side until char marks appear, but still pink inside.
Leave to rest for a couple of minutes before serving.