Diana Kennedy sank into a dimpled leather chair at the Hotel Emma in San Antonio, leaned over her glass of Scotch and told me that the real enemy of every writer was mediocrity. This was in 2019, when she was 96, and decades of deep culinary research had made her a leading authority on Mexican food for British and American home cooks — both despite the fact that she was a British-born white woman, and because of it. I thought […]