I ate quite a lot of ratatouille when I was Lord Rector of Aberdeen University because it seemed to be the staple diet of students, especially towards the end of term when they were running out of money. And of course they would put anything into it that was cheap and they could get their hands on; no doubt it kept them regular. But this is the proper, Niçoise ratatouille. Don’t peel your aubergines completely - leave some strips of skin to add colour and texture.