Preheat oven to 400F.
In a medium bowl whisk together eggs, parsley, Parmigiano-Reggiano, cream and some salt and pepper. Set aside.
Trim zucchini ends and grate each one lengthwise over a box grater to take the flesh off without pulling out any of the seeds. Place a medium skillet over medium-high heat with 2 turns of the pan of EVOO, about 2 tablespoons. Saut the leeks and zucchini until tender, about 5 minutes. Season with salt and pepper.
Baste the inside of each cup of a six-cup muffin pan with some melted butter. Divide the leek mixture between the six cups. Push the mixture into the bottom and up the sides of each cup to form a nest. Divide the egg mixture between the six cups, pouring it directly into each next. Bake until the eggs are set and puffed, 8 to 10 minutes.
Let set a minute before removing. Serve warm.