It's a sure sign we're in the middle of spring.
I found these forest treats at the University District Farmer's Market on Sunday. The season is mercilessly brief for fiddlehead fern fronds... They'll probably be impossible to find by the time I return from my trip to Japan. So, even though I have been trying to reduce the perishable contents of my refrigerator as fast as possible, I couldn't resist picking up some fiddleheads before I go.
Warabi, as fiddleheads are called in Japanese, are typically briefly blanched in Japan to remove aku (roughly: bitterness, astringency, the "unclean" parts of food) before they are incorporated into other dishes. Often a bit of baking soda is used when blanching this type of spring mountain greens, which slightly softens them and also removes more of the traces of enzymes that, given long term heavy consumption of the plant, can lead to some health problems. This blanching technique is always used in Japan, though I think it's sometimes neglected in the US where we seem to want to immediately toss these in a pan with olive oil.
In the Pacific Northwest, my understanding is that the Chinook tribe traditionally cooked these with oil extracted from oolichan fish, which also run in the spring.
For me, I'm happiest with a simple Japanese-style preparation.
I like zenmai, a similar frond common in Japan, on top of a bowl of warm soba, but for warabi I usually just make a kind of simmered ohitashi.
This is just Japanese soup stock (dashijiru), seasoned with the typical combination of mirin, Japanese soy sauce, salt, and a bit of sugar, all done to taste. Once the sauce comes to a simmer, I just add the warabi and simmer for a few more minutes. The prior blanching will also help preserve the color during the second exposure to heat.
Warabi is a little bitter, but the overall flavor is reminiscent of asparagus, if perhaps a bit more intense in flavor. Unlike most ohitashi, I serve this warm. As a result, the dish is almost like nimono, even though it's not cooked quite as long.