I guess it would depend - almost completely cave dwarves would be tricky, but in most settings, caves are for, unsurprisingly, mining first of all.
So assuming dwarves that sleep/eat in some really big caverns etc. that are prevalent in the settings, they still can hoard sheep, goats, mountain goats and some other more exotic/fantasy herbivores. So pretty much standard highland food source.
Then hunting and collecting different stuff - fishing also, there are streams in the mountains and below surface. Maybe with some interesting fantasy fish.
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