Henry Oliver's Substack on the Hobbit mentioned this in passing, and its title suddenly reminded me how thoroughly Potter dominated my childhood, which I had hitherto completely forgotten. I went to Wikipedia for a refresher and saw it's available online for free so I just read it.
The story itself is a nice heartwarming Christmas tale, with the tailor's cat going on a mini Scrooge-esque journey, to everyone's benefit. It's surprisingly complex in its archaic writing for what is ostensibly a kid's book: the substack mentioned it because of its odd prosody, the way the words ebb and flow in "lulling rhythms", and I have to imagine this is first place I read words like 'wainscot' and 'groat' and shit. Still no clue what taffeta is, even.
The restraint she shows in making up the legend that animals only talk like humans on Christmas Eve is great, especially because in other Beatrix Potter books the animals are normally completely anthropomorphic. The weird in-between world this book lives in, where Simpkin the cat can simultaneously go out to buy milk and silk, but can still only communicate in real cat noises, is delightfully stupid. It makes the twist (ha. [that's mildly funny if you read it I promise lol]) feel that much more special because the mice could only help the tailor on this particular (holy) day.
It's very linked to the illustrations for me, which are faithfully recreated in the Wikisource page. They show just how meagrely and miserably the tailor lives, in a cramped room full of dingy dark browns and shadowy indiscernable furniture, and how magical Christmas Eve in Gloucester, with all the animals singing and the whole town almost glowing, looks in comparison.
I associate this very strongly with childhood Decembers at my grandparents, back when Christmas was exciting, banging this out while a CD of Nat King Cole's interpretations of holiday classics slowly wore itself out. Entirely biased 5* for this alone, but it is also just a fundamentally nice story, executed extremely well by a great writer
EDIT: MATE *SHE* DID THE ILLUSTRATIONS TOO ARE YOU DUMB. PUT SOME RESPEK ON HER NAME
Edit 2: she also invented the lake district???? I think I am having a atroke