To blanch fiddleheads, the recommended time is generally about 2 minutes in boiling water. After blanching, they should be immediately plunged into ice water to stop the cooking process and preserve their color and texture

. Here are key points from multiple sources:

• Blanch fiddleheads in boiling water for 2 minutes, then transfer to an ice bath

• Some sources mention blanching times ranging from 1 to 3 minutes, with 2 minutes being typical

• Avoid overcooking (e.g., 10-15 minutes) as it can make fiddleheads mushy and lose nutrients

• After blanching and freezing, fiddleheads should be boiled for about 10 minutes before eating to ensure safety

In summary, blanch fiddleheads for about 2 minutes in boiling water, then cool them quickly in ice water. This process removes bitterness, kills harmful enzymes, and prepares them for further cooking or freezing.