Preheat your oven to 375°F (190°C). Lightly spray a small individual baking dish with olive oil.
Thaw the frozen spinach and squeeze it very dry using a clean kitchen towel or paper towels to remove all excess moisture.
In a medium bowl, whisk together the egg, egg whites, and cottage cheese until well combined.
Fold in the squeezed spinach, crumbled feta cheese, chopped green onions, fresh dill, sea salt, and black pepper.
Lay one sheet of phyllo dough into the baking dish, allowing the edges to hang over, and lightly spray with olive oil.
Fold the second sheet of phyllo and place it on top, then pour the spinach and egg mixture into the center.
Fold the overhanging edges of the phyllo dough over the top of the filling to partially cover it.
Lightly spray the top with olive oil and bake for 30-35 minutes until the filling is set and the pastry is golden brown and crispy.