Fiddleheads are the young coiled fronds of ferns, which begin to appear in early Spring.
Nearly all ferns have fiddleheads, but the edible ones are from the Ostrich Fern.
They are delicious, with a delicate grassy, spring flavor that I would most closely compare to asparagus, although fiddleheads are really in a class all their own.
And of course, they are healthy! They contain fiber, vitamin C, vitamin A, and omega-3 fatty acids.