Preheat your oven to 375°F and lightly grease a small oven-safe baking dish with a tiny bit of oil.
Place the thawed spinach in a clean kitchen towel and squeeze firmly over the sink until all excess moisture is completely removed.
In a medium mixing bowl, whisk together the large egg, egg whites, and non-fat Greek yogurt until the mixture is smooth and well combined.
Fold in the squeezed spinach, crumbled feta cheese, chopped green onion, fresh dill, and fresh parsley.
Season the mixture with sea salt, black pepper, and garlic powder, then stir until the ingredients are evenly distributed.
Pour the spinach and egg mixture into the prepared baking dish, spreading it out into an even layer with a spatula.
Take the two sheets of phyllo dough and lightly brush them with the olive oil, then gently scrunch or tear them into pieces and scatter them over the top of the spinach mixture.
Place the dish in the oven and bake for 25 to 30 minutes until the phyllo topping is deeply golden and the egg filling has set through the center.