Dahlia Travers has to constantly be on the lookout for covetous gourmands who would steal the chef supreme, Anatole, from the kitchens of Brinkley Manor. His reputation is such that a recent dinner party there included five such miscreants: her sister Agatha, one J. Bashford Braddock, Sir Watkyn Bassett, Dame Daphne Winkworth, and Roderick Spode. These wicked dinner guests had heard great things about various dishes of Anatole's, and had requested them in particular. They were served in this order: the onion soup, the trout amandine, the chateaubriand ala financier, the cassoulet, and the mousse au chocolat.
Fortuitously, there were also five heroic souls present who had each discovered the ulterior motives of one of the villians. The Allied troops consisted of: Dahlia, Uncle Tom, Beach the Butler, Bertie Wooster, and his manservant, Jeeves. In order to foil the plans of the assembled villians, each had snuck into the kitchen and adulterated the sauces of Anatole's divine output with a spoiler: one used tabasco, another maple syrup. Anchovy paste, bitters, and vinegar were also employed as toxins. The end result was undoubtedly the vilest repast that Monsieur Anatole has ever committed to chafing dish, and the entire household was blue about the gills from the experience (except Jeeves, who wisely ate nothing but bread rolls). All parties departed without making Anatole any offers. Anatole, unfortunately, had a nervous breakdown on tasting the returns and had to spend a fortnight at Lourdes to recuperate.
Can you determine from the seven clues below which snake in human form coveted which dish, who foiled their plans, and what they poisoned it with?
PS - It has been brought to my attention that Seppings should be buttling Brinkley Manor, not Beach. Er ... perhaps Lady Constance lent Beach to Aunt Dahlia while Seppings recuperated from a bout of lumbago!