Jisho

Just based on the definition in the entry, "mouth watering" sounds right, but "jaw dropping" is a lot broader. That's an issue of English meaning though, nothing specifically about ほっぺたが落ちる.

Expressions should probably never be directly translated because the meaning will not be the same. I would see it as a coincidence that there are expressions in English with similar meanings and not worry about that. The meaning of the Japanese expression here is just, as stated in the entry, that something is very delicious.