Lethal Luncheon

A Puzzle Lady short story. Cora Felton wasn't happy about having to give
a talk on crossword puzzles at a charity luncheon, largely because the
Puzzle Lady was actually a total fraud and couldn't solve a crossword
puzzle with a gun to her head, but she cheered right up when one of the
luncheon guests got poisoned, and she was able talk instead about how to
catch a killer. (Recipe included!)