Preheat your oven to 375°F (190°C).
In a non-stick skillet over medium heat, add the olive oil and sauté the finely diced yellow onion until it becomes soft and translucent.
Add the ground turkey to the skillet, breaking it into small crumbles with a spatula, and cook until fully browned and no longer pink.
Toss in the fresh spinach and cook for 2-3 minutes until completely wilted, then remove the skillet from the heat and drain any excess liquid thoroughly.
In a medium mixing bowl, whisk together the large egg, egg whites, chopped dill, chopped parsley, garlic powder, sea salt, black pepper, and a pinch of nutmeg.
Fold the cooked turkey and spinach mixture along with the crumbled feta cheese into the egg mixture until well combined.
Transfer the filling into a small individual-sized oven-safe baking dish or ramekin.
Take the phyllo sheet, lightly mist it with a tiny bit of water or oil, crinkle it up loosely, and place it over the top of the filling to create a textured crust.
Bake for 20-25 minutes until the egg filling is set and the phyllo topping is golden brown and perfectly crispy.