Man, I've been thinking about this one since I finished the third book last week. The core plot of 'Frivolous Veronica Lancet' isn't actually about Veronica being frivolous at all—that's the whole joke. It's a mystery series disguised as a high-society satire. In the first novel, Veronica, who everyone writes off as a shallow socialite, stumbles onto a murder at a gala. The police dismiss her, so she uses her gossip network and encyclopedic knowledge of designer fabrics and who was having affairs with whom to piece together the real killer. The plot hinges on her weaponizing people's underestimation of her. It's less a whodunit and more a 'how-the-hell-is-she-going-to-prove-it'. The ending has this fantastic scene where she reveals the culprit by analyzing the stitch pattern on a torn glove, connecting it to a specific tailor and, by extension, the murderer's alibi.
I heard some readers complain the mystery itself is simple, but that's missing the point. The fun is in the execution, watching Veronica navigate this glittering, vicious world everyone thinks she's just a part of, not an observer of. The sequels build on this, where her reputation as a 'silly detective' actually becomes an asset, letting her get away with questions no 'serious' investigator could ask.