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.