From Wikipedia‘s incomplete list of the fictional characters featured in the Blandings Castle stories of P. G. Wodehouse:
*Lord Emsworth’s short and dumpy sister, who resembles a cook, albeit a passionate one. The wife of Colonel Egbert and mother of Veronica, Hermione has all her sisters’ fear of one of the family marrying beneath them, and is incensed when Bill Lister, unsuitable suitor of her niece Prudence, mistakes her, as so many do, for a cook, in Full Moon.
When we meet her again in Galahad at Blandings, she is for a spell acting as chatelaine at the castle, in the absence of her sister Connie, but gives it up in the face of her brother’s impossible ways; we learn that once, as a child, she struck Galahad over the head with her doll, laying him out cold.
Galahad at Blandings is a novel by P. G. Wodehouse, first published in the United States on 31 December 1964 by Simon & Schuster, Inc., New York under the title The Brinkmanship of Galahad Threepwood, and in the United Kingdom on 26 August 1965 by Herbert Jenkins, London.
From Wikipedia‘s plot summary:
“…Meanwhile, Lady Hermione has learned from Emsworth that Tipton had lost all his money in the stock market crash and is now impoverished. She rushes up to London to instruct Veronica to break the engagement in a letter to be delivered by the next post. When Colonel Wedge receives Tipton, who is driving a Rolls-Royce and brandishing an £8000 necklace for Vee, he asks Gally to intercept the letter, which Gally is pleased to do. Gally goes a step further and gives the letter to Sam. On Hermione’s return, when Beach informs her that the man who stole his watch is at the Castle impersonating Augustus Whipple, Gally threatens to deliver the letter to Tipton unless Hermione allows Sam to stay. Hermione tries searching Sam’s room, but only succeeds in losing Wilfred his job with Dame Daphne, when her son Huxley discovers him singing in the corridor as a signal to his aunt…”