。
She is a short-story writer.
Literal
She [topic-は] short-piece novel writer is.
短編小説 is a Sino-Japanese compound — 短編 ('short piece') + 小説 ('novel / fiction') — for the genre 'short story.' Japan has a strong literary tradition in this form, with major figures like Akutagawa Ryūnosuke and Murakami Haruki publishing widely in it. 作家 ('writer / author') specifies a literary author, contrasted with 著者 (a more neutral 'author' that might apply to non-fiction).