This is the front cover of the "Flan wants to die" doujin by yuu. There is a hard translation out of this that can be read here: https://imgur.com/a/aPQJg , It is really good and I highly reccoment reading it.

However the original Japanse version is still missing.

Apparently a lot of her old works are missing. I hear once she got big she deleted stuff on per Pixiv and past derivative works. Does anyone by chance know where I can see those? Surely someone must have a collection somewhere