I googled “bowl of cornflower”, and the first page had (a) stuff about whisking lemon juice into a bowl of cornflower paste, as well as (b) what looks quite like a quote from a mystery novel: “The police thought that she could have been poisoned as the maid Gladys mentioned Mr Jones prepared a bowl of cornflower for his wife and took it to her in her bedroom.” (And then, from another site: “She had also prepared a bowl of cornflower for Mrs Jones to calm her stomach but Miss Clark had drunk this, despite the diet she was on for her constant weight problem.”)