Preheat your oven to 375°F (190°C).
In a non-stick skillet over medium heat, sauté the sliced green onions and fresh spinach until the spinach is completely wilted and any excess moisture has evaporated.
In a medium mixing bowl, whisk together the eggs, egg whites, non-fat Greek yogurt, sea salt, black pepper, and ground nutmeg until the mixture is smooth and well combined.
Stir the sautéed spinach and onion mixture into the egg bowl, then fold in the crumbled feta cheese and chopped fresh dill.
Lightly brush a small oven-safe baking dish (about 6 inches) with a small amount of the olive oil.
Layer the phyllo dough sheets into the dish one at a time, lightly brushing each sheet with the remaining olive oil and allowing the edges to hang over the sides of the dish.
Pour the spinach and egg filling into the center of the phyllo-lined dish.
Gently fold the overhanging edges of the phyllo dough back over the top of the filling, leaving the center slightly exposed for a rustic look.
Bake for 25 to 30 minutes until the filling is firm and set, and the phyllo crust is a deep golden brown.