Asparagus
From Cantr II Wiki
Asperagus can be eaten raw, at a rate of 43 grams per day. It can be harvested at 300 grams per day without tools, a shovel will double the maximum output and by using an asparagus harvest knife, one can boost the output to 2055 grams per day.
This makes asperagus a quite potent food, because with one day of work, and the proper tool, a farmer can collect enough of it for 50 days.