I don't have a specific recipe for you (I also just usually sautee them in whatever else I'm cooking that night - a few nights ago, it was a very light butter/oil/lemon/herbs sauce), but I can give you this hint: parboil (or steam) them before you sautee them. Don't do it for too long, as you want them to stay crispy, but it really seems to help with the flavor a bit.
(As I'm writing this, I just realized that you're probably talking about frozen fiddleheads. In that case, I'm not sure that my above hint is particularly applicable)
My mother tends to use the same recipes she uses for spinach or kale when she cooks fiddleheads, and it seems to work well.