How to Make It
Preheat the oven to 375°. Fill a large pot halfway with water and bring to a boil. Add the spinach by the handful and cook until wilted, 1 minute. Drain and let cool slightly, then squeeze out as much liquid as possible. Coarsely chop the spinach.
In a large bowl, whisk the eggs with the feta, 1/4 cup each of the Pecorino and Parmesan and a generous pinch of pepper. Stir in the spinach. Pour the mixture into a shallow, buttered 2-quart baking dish and sprinkle the remaining 2 tablespoons each of Pecorino and Parmesan on top. Drizzle the oil over the pie and bake for about 40 minutes, or until golden and sizzling. Let cool for 10 minutes then serve.