Banana flowers (aka banana blossoms, or banana hearts) are the blossoms from a banana tree. They're a completely edible delicacy and are commonly used in salads, curries, and soups adding a subtly sweet, floral tropical taste.
The most delicate parts, the yellowy-white florets, require removal, cleaning, and soaking in acidulated water in order to mitigate some of the bitterness they possess. The intermediary leaves, which are pale pink in color, are also edible, too, and should be soaked as well.