Preheat your oven to 375°F and lightly grease a 6-inch oven-safe skillet or small baking dish with a drop of olive oil.
In a medium pan over medium heat, sauté the chopped scallions and minced garlic in 0.5 tsp of olive oil for 2 minutes until fragrant.
Add the fresh spinach to the pan and cook until completely wilted, then transfer to a colander and press out all excess moisture with a spoon.
In a mixing bowl, whisk together the large egg, egg whites, Greek yogurt, lemon zest, oregano, sea salt, and black pepper until smooth.
Stir the wilted spinach and crumbled feta cheese into the egg mixture until evenly distributed.
Lay one sheet of phyllo dough into the prepared baking dish, brush lightly with the remaining olive oil, and layer the second sheet on top, allowing edges to overhang.
Pour the spinach and egg mixture into the center of the phyllo and gently fold the overhanging edges toward the center to create a rustic border.
Bake for 25-30 minutes until the filling is set and the phyllo crust is beautifully golden brown and flaky.