For the spiced lamb, sear the slices of lamb in a hot frying pan until lightly browned on both sides. Add the pepper and garlic and cook for 3-4 minutes.
Add the chilli flakes and ground coriander and stir. Pour in the vegetable stock and simmer for 10 minutes.
For the sweet and sour leeks, melt the butter and brown sugar together in a pan until a caramel forms.
Add the baby leeks and cook for 3-4 minutes, or until soft. Add the red wine vinegar and cook for a further minute.
To serve, place the lamb on a warm plate and serve the leeks on the side. Top with the grated chocolate and Greek yoghurt.
