Preheat your oven to 375°F (190°C).
Place the thawed spinach in a clean kitchen towel and squeeze vigorously until every drop of moisture is removed and the spinach is very dry.
In a large mixing bowl, whisk together the whole egg and liquid egg whites until well combined and slightly frothy.
Stir in the squeezed spinach, crumbled feta cheese, sliced scallions, chopped fresh dill, sea salt, black pepper, and ground nutmeg.
Lightly brush a small oven-safe baking dish with a tiny amount of the olive oil.
Lay one sheet of phyllo dough into the dish, allowing the edges to hang over the sides, and brush very lightly with olive oil.
Place the second sheet of phyllo on top at a different angle to cover more area and brush again with the remaining oil.
Pour the spinach and egg mixture into the center of the phyllo dough.
Gently fold the overhanging edges of the phyllo over the top of the filling to create a rustic, crumpled border.
Bake for 30-35 minutes until the egg filling is completely set and the phyllo pastry is golden brown and perfectly crisp.