Preheat your oven to 375°F and lightly brush a small oven-safe baking dish with a tiny amount of olive oil.
Sauté the fresh spinach and sliced green onions in a pan over medium heat until completely wilted and tender.
Place the cooked spinach in a clean kitchen towel and squeeze firmly to remove all excess liquid to prevent a soggy crust.
In a large mixing bowl, whisk the whole eggs and egg whites together until smooth and slightly frothy.
Fold in the crumbled feta cheese, chopped fresh dill, sea salt, black pepper, and ground nutmeg.
Stir the squeezed spinach and onions into the egg mixture until the filling is well combined.
Lay one sheet of phyllo dough into the prepared dish, allowing the edges to hang over, and lightly brush with the remaining oil.
Place the second sheet of phyllo on top, then pour the spinach and egg mixture into the center.
Fold the overhanging phyllo edges back over the filling and bake for 25 to 30 minutes until the center is set and the pastry is golden brown.
Remove from the oven and let the pie rest for five minutes to allow the filling to firm up before slicing into squares.