In my weekly conversation time with a Japanese friend I wanted to ask her what were her favorite Japanese food, drink, etc. I asked her in the form of
何が大好きな日本の食べ物か
and she corrected me, saying that the natural informal way to ask would be
日本の食べ物で大好きなものは何？
I'd like to confirm if, in this context, で indicates 'among all'.
For practical purposes, understanding this で as an abbreviated の中で is probably fine.
However, it doesn't actually feel like that to me. Consider this sentence:
最も好きな食べ物は何ですか？
versus
食べ物で最も好きなものはなんですか？
The essential parts are just 食べ物, 最も好き, 何 and we put them together in some syntactically acceptable order.
最も好きな食べ物は何ですか？
What is your favorite food?食べ物で最も好きなものはなんですか？
Food-wise, what do you like best?
Sure, there are nuance differences associated with these different syntactic structures, but in this case it's probably beside the point. In the second form, what's literally going on is that you're adjectivizing 食べ物 to describe what kind of 好きなもの you're talking about. Here's a crappy-sounding, direct translation:
What are your most liked edible things?
but it gets the syntax across, hopefully.
