There are two types of people in this world: those who think Margaret Costa is one of the most influential food writers of the twentieth century, and those who haven’t yet read her. There’s a good chance that, if you fall into the latter camp, you haven’t even heard of her. Costa didn’t enjoy the of-her-own-time influence of Elizabeth David, Claudia Roden or Jane Grigson, or the revival or rediscovery that we’ve seen for Patience Grey, Arabella Boxer or Dorothy Hartley. But for those in the know, it’s impossible not to mention Margaret Costa in the same breath. She is, in many ways, the cookery writer’s cookery writer. Delia Smith describes her as ‘the best-kept culinary secret in the entire history of British cooking’. Indeed, when Simon Hopkinson couldn’t lay his hands on a copy of her then out-of-print cookbook, Delia gave him hers. He thought calling it a classic was ‘almost an understatement’, while Nigel Slater has said, ‘If I had to choose only one book to cook from for the rest of my life it would be this one.’