There are no restaurants near the Monastery. So I would advice you to get something substential in Zhovkva. But, there is a small shop outside of the Krekhiv Monastery where you can get a cup of coffee or tea, ice-cream and some sweets. you can take it outside to a nearby wooden house, kolyba (shepherd’s log) and enjoy while waiting for a mini-bus.
Zhovkva still lacks places to dine, but it will catch up. for a coffee and a snack you might consider going to Pidsinnya (trans. as arched gallery), located in the... arched gallery of the main market building. it's a nice place, according to the owner opened for tourists and very crowded in May and October. since I came there in June around 11 am, it was completely empty.
Favorite Dish: I had a cup of Turkish coffee and a roll purchased in a nearby shop (on the owner's advice ;) and was completely happy and ready to continue my exploration