Step 1

Heat 1 tablespoon oil in a large skillet or large pot over medium-high heat. Add red onion, spring onions (or scallions) and garlic. Cook, stirring often, until softened, about 4 minutes. Working in batches, add spinach to the pan and cook, tossing, until wilted and all the liquid has evaporated, 15 to 25 minutes total. Transfer to a bowl, discard the garlic and let the spinach cool completely, about 25 minutes.

Step 2

Meanwhile, preheat oven to 375°F. Coat a 9-by-13-inch baking dish with cooking spray.

Step 3

Unroll phyllo sheets and carefully place them between 2 damp kitchen towels. (This helps prevent the sheets from tearing.)

Step 4

Add feta, eggs, hartwort (or chard), chervil (or parsley), dill, nutmeg and pepper to the spinach mixture and stir until combined.

Step 5

Place the remaining 3/4 cup oil in a small bowl for drizzling. Transfer 1 tablespoon of the oil to a separate small bowl; reserve for brushing the border. Lay the first phyllo sheet on the bottom of the prepared pan, letting it drape over the sides. Drizzle with about 1 1/2 teaspoons oil. (Do not brush the phyllo; you don't want the sheets to stick to one another. Drizzling makes the phyllo crunchier!) Repeat with 3 more phyllo sheets.

Step 6

Spread the filling evenly over the phyllo base. Drizzle the filling with about 1 1/2 teaspoons oil. Cover the filling with the remaining phyllo sheets, drizzling each sheet with a little oil. Gently tuck in the overhanging sheets to create a border. Brush the border with the reserved 1 tablespoon oil. Score the surface with a sharp knife, marking 12 rectangles and cutting just down to the filling. Drizzle the top with the remaining oil.

Step 7

Bake until the pie is golden brown and the filling is hot, 55 to 60 minutes. Let cool for at least 15 minutes before cutting.