Preheat your oven to 375°F (190°C).
Mince the garlic and roughly chop the spinach.
In a non-stick skillet over medium heat, sauté the garlic and spinach until the spinach is completely wilted and any excess moisture has evaporated.
In a medium mixing bowl, whisk together the liquid egg whites, whole egg, nonfat Greek yogurt, sea salt, and black pepper until the mixture is smooth and well-combined.
Stir the sautéed spinach, crumbled feta cheese, and chopped fresh dill into the egg and yogurt mixture.
Pour the mixture into a lightly greased 6-inch oven-safe baking dish or individual ramekin.
Take the phyllo sheets and gently scrunch or fold them to fit the top of the baking dish, layering them over the egg mixture.
Lightly brush the top of the phyllo with the olive oil to ensure a golden finish.
Bake for 25-30 minutes, or until the phyllo is golden brown and the custard center is firm and no longer jiggles.
Let the pie rest for 5 minutes before serving to allow the custard to set completely.