Smoky aubergine with tomatoes

In Iran an aubergine purée is almost always part of a meze spread and it is usually my favourite dish. Cyrus, the wonderful cook at my local Iranian restaurant, Sufi, in west London, taught me the trick of making the walnuts we buy here, which are often dry, taste like the fresh ones I remember in Iran. If you are serving this purée as a first course, try to find some Iranian flat bread to accompany it.