Step 1

Heat the oven to 375°F with a rack in the middle position. Place a colander in a medium bowl and set near the stove.

Step 2

In a 12-inch cast-iron skillet over medium-high, melt 1 tablespoon whole butter. Add a few large handfuls of the spinach and kale, then cook, stirring and turning with tongs, until wilted, 1½ to 2 minutes. Transfer to the colander. Wilt the remaining spinach and kale in the same way without adding more butter; set aside.

Step 3

In the same skillet over medium, melt 2 tablespoons of the remaining whole butter. Add the leek, garlic, ¼ teaspoon salt and ½ teaspoon pepper. Cook, stirring occasionally, until the leek is tender, 4 to 6 minutes (if the leek begins to brown or stick to the skillet, stir in 1 to 2 tablespoons water). Remove the skillet from the heat and let cool for about 10 minutes.

Step 4

Meanwhile, in a large bowl, whisk the eggs to combine. Add the feta, ricotta and dill, then whisk to combine. Using your hands, squeeze the moisture from the greens; you should have about 3 cups squeezed greens. Add the greens to the egg-cheese mixture and stir until well combined, then transfer to the skillet (it’s fine if the skillet is warm to the touch but it should not be hot). Stir to incorporate the leeks, then distribute the filling in an even layer in the pan.

Step 5

Brush 1 phyllo sheet on both sides with some of the melted butter, then scrunch it loosely and place on top of the filling. Repeat with the remaining phyllo and butter, covering the entire surface of the filling. Drizzle any remaining butter over the top.

Step 6

Bake until the phyllo is golden brown, about 35 minutes. Cool for about 10 minutes before slicing and serving.