First off, glad to see the farming cross post or I wouldn't have seen this comm so I could sub!
We don't do much fruit right now, but I'm hoping to change that next year. My favorite not-a-fruit-thats-easy would probably be carrots or lettuce.
From previous efforts, I'd probably say strawberries. We had moved, so haven't done strawberries in a few years, but hoping to get some property for us to live/farm over the next year and strawberries will definitely be on the list for us.
Edit: We do a community garden right now, the lack of fruit is due to some of the rules of the garden.