Well if you can forage for them, get about four big handfuls, cut the stem close to the curl. Then here's how I cook them:

• Get two pots of water boiling. And keep one bowl of ice water aside.
• blanch the fiddleheads in the first pot for 5 minutes.
• then using a metal frying scoop, scoop them out and transfer to the second pot and blanch for another 5 min.
• then transfer to the ice bath to stop them from cooking further.
• heat a pan on medium heat and add butter
• saute the fiddleheads
• serve with salt and pepper