Is it this one?

FelixFilm is adapted from NEKO WORKs game of the same name, original name: ネコぱら OVA, Chinese name: Chocolate and Vanilla OVA, English name: NEKOPARA OVA

P.S: The author Sayori has already confirmed that Vanilla's name is "Vanilla". "The name "Vanilla" is not an official translation...

Another point: "Vanilla" is called "雲呢拿" in Cantonese and "香草" in Mandarin, especially in ice cream. The word "vanilla", in Cantonese, is "雲呢拿", and in Mandarin, it means "vanilla".