I lectured someone the other day—not harshly, but with firmness, because we're dealing with life and death, after all—about eating unidentified wild mushrooms. The cardinal rule, I explained, is to always sample a new species in the company of an experienced mycophagist who can point out diagnostic field marks. Watching a real person positively ID a real mushroom is important because books and field guides are sometimes misleading, especially with their use of pictures. There's more variance in the fungal kingdom than the animal kingdom; while a species of bird can generally be counted on to exhibit a specific set of traits (e.g. wing-bars, eye-rings, coloration, etc.), a species of mushroom might look quite different depending on locale, growing conditions, age, and other factors. In many cases the variations actually represent different species within a genus that haven't been recognized yet. Think of all the variance in morels, for example.
Sometimes I wonder if I should be following the same advice with fiddleheads. Several sources say there are no poisonous species of fiddlehead (not counting the carcinogenic bracken fern). Is this a general rule based on a limited sample, or have all varieties of fiddlehead really been tested for edibility? Somehow I doubt it. Certainly some are bitter or otherwise unappetizing. I would never try to eat a sword fern fiddlehead, for instance.
On my hike the other day I collected a bagful of fiddleheads. I have no idea what species they were. Like the wood fern fiddleheads I found the other day, they had fairly prominent paper sheathes. But these fiddleheads were smaller and more delicate, and usually within a clump I could find one or two that were relatively free of the sheath and easier to clean.
In the end, I ate them anyway—and they were fantastic. I boiled the fiddleheads for 10 minutes, then made a cream sauce with them which I poured over fried rockfish and buttered orzo. My timing was slightly off, resulting in a sauce that had a consistency more like cream of spinach. No matter, it was delicious way beyond my expectations. Fiddleheads are the bomb.
Fiddlehead Cream Sauce (for 1)
1 shallot, finely chopped
1 dozen fiddleheads, boiled
1-2 tbsp butter
1/4 cup (or more) heavy cream
seasoning to taste
Saute the shallot in a tablespoon or so of butter for a minute or two. Add fiddleheads and stir. Season with salt and pepper to taste. Add cream. I used half-and-half, but heavy cream is always better if you have it on hand. Allow to thicken and pour over fish, meat, pasta, whatever.
[Sorry about the photo. The meal was actually much more appetizing than the picture. My little digi point-and-shoot reaches its limit on these low-light, dinnertime snapshots. I plan to get an SLR one of these years... -Ed.]