Mix the lamb with the yogurt, turmeric, ginger and garlic pastes, cumin, coriander and mustard seed powder, poppy seed paste and salt. Leave to marinate in a non-metallic bowl for as long as possible or at least until you chip and cook the next batch of ingredients.
Once tender, stir in the garam masala and black pepper; check and adjust seasoning. Always make sure there is enough water in the pan for a little gravy by adding extra from the kettle or cook the lamb over a high flame to dry of any excess water. Stir in the coriander and serve.
I added some french beans to the sauce and served with basmati rice, it would definitely have looked prettier if I had had some coriander!!