- Bring two large pots of salted water to a boil. Plunge the fiddleheads into the first pot and blanch for 1 minute. Drain and discard the water. Repeat with the second pot of boiling water. Plunge the fiddleheads into a bowl of ice water to stop the cooking. Drain and set aside.
- In a bowl, combine all of the ingredients. Season with salt and pepper. Set aside.
- In a large bowl, combine the spinach and apples.
- In a skillet over medium heat, soften the shallots and fiddleheads in the butter for 3 minutes. Add the shredded duck meat and cook to warm through. Arrange the fiddleheads and duck meat over the spinach. Add the dressing to taste and toss to combine. Adjust the seasoning.
- Serve immediately.