American missionary Fanny Crosby composed more than 8,000 hymns, and Anglo-Irish hymnwriter and poet Cecil Frances Alexander is famous for three hymns.
More women composers and performers on the New Music Show tonight, including a funny and interesting new composition for these Covid times by Jennifer Walshe, and works by Tansy Davies and Erika Fox
I don't know if there is strict criteria for considering someone a "classical composer" - as in quantity of compositions, for example - but I would put forward the performance artist Laurie Anderson, whose earliest pieces (sadly few recorded) included a symphony composed for automobile horns and a classical violin solo composed to be played while standing on a block of ice (the duration of the piece depended on how long it took the ice to melt, so we're in John Cage territory here). She has also worked with Philip Glass and the Kronos Quartet and debuted a new performance art/classical mashup called The Art of Falling just last year.
I really don't see what the point is of these sorts of things? Why does ANY gender have to be attached to it? A human being wrote or composed this or that. That should be the end of the story. Why does it matter that one of them was born into a female body and another was born into a male body? Like the OP said, it's like saying that someone that wrote something WITHOUT a dick is something amazing or to be exhibited in a freak show.
A new record label La Boîte à Pépites was formed earlier this year by cellist Héloîse Luzzati, specifically to release records by neglected women composers and conductors. The first three recordings were released as digital downloads on the 1st of April, and will be released as a set of CDs on the 1st of September; these are of works by Charlotte Sohy
(Update) Charlotte Sohy is now represented in Classical World.