Preheat oven to 350 degrees Fahrenheit.
Boil fiddlehead ferns for 5-7 minutes, remove from heat and strain water.
Line a large baking sheet with parchment paper or a silicon mat.
Place fiddleheads in a single layer on lined baking sheet and put aside.
Meanwhile, add parmesan, breadcrumbs and garlic to food processor. Pulse until fully mixed, and garlic is chopped down to roughly the same size as breadcrumbs.
Sprinkle breadcrumb mixture evenly over each fiddlehead, piling the topping in a little mound on each fern.
Spray evenly with olive oil, evenly coating the breadcrumb topping.
Slide sheet into oven and bake for 15 minutes.
While fiddleheads are baking, mix up dipping sauce by stirring mayonnaise, lemon zest and lemon just together, add black pepper if desired.
Remove ferns from oven and serve alongside the lemon dipping sauce, enjoy!