Do you get overexcited at the market and buy too many greens and herbs, only for them to wilt in the crisper drawer? Yeah, me too. Don’t worry: This mixed green spanakopita is here to rescue them all! Use whatever assorted tender greens and herbs you’ve got: Swiss chard, arugula, carrot and radish tops, parsley and dill. The key here is to stick with quick-cooking, tender greens — hearty collards or kale won’t have enough time to get tender in this pie. If you’re not sure if your greens are tender, give them a taste. If they are pleasant to eat raw, they are tender. If they taste stringy and tough, save them for braising in a pot of beans instead.
Technique tip: Don’t rush thawing phyllo in the microwave where it can dry out and crack. Instead, leave the package in the fridge to slowly thaw overnight. Tightly wrapped, store leftover phyllo in the fridge for up to 2 weeks (do not re-freeze). Use it to make baklava, cheese-filled triangles, strudel or crinkle cake.
Swap option: Swap the fresh tender greens for two 9-ounce bags of frozen spinach (thaw before using; don’t squeeze out the excess liquid). Make it vegan: Swap the feta for vegan feta or medium firm tofu, omit the egg and cool fully before serving.
Adjust the oven rack to the lower-middle position and heat to 400 F. Brush a 10-inch skillet (or 9-inch-deep dish pie plate) generously with olive oil and set on a sheet tray.
In a large bowl, combine greens, herbs, olive oil, feta brine (or lemon juice), salt and pepper. Use your hands to mix everything together and massage the greens until darkened, wilted and silky, about 3 minutes. (The combo of salt, acid and massaging breaks down the greens, so they cook faster.) Taste and add more salt and pepper, if needed.
Add the couscous (or bulgur) and egg, and mix until evenly combined. (The couscous/bulgur soak up the moisture released from the greens and prevent your pie from having a soggy bottom.) Add the feta and mix until evenly combined.
Unroll the thawed phyllo and keep it covered with a damp towel while you are working. Working with 1 sheet at a time, lay in the skillet (or pie pan) with the excess draping over the rim and brush generously with olive oil. Repeat until you have a total of 8 sheets of phyllo lining the pan, each sheet placed perpendicular to the previous one, brushing with olive oil before adding the next.
Add the filling, gently pressing it down into one even layer. Fold over the phyllo overhang then drape the last 4 sheets on top, scrunching them to cover the top. Drizzle with olive oil, then use a sharp serrated knife to cut into portions (it’s enough to just cut through the top layer of phyllo, this makes it easier to get clean slices after baking).
Bake until the top is browned and crispy, about 45 minutes. Cool for at least 15 minutes before serving. Slice again with a sharp serrated knife. Eat hot, cold or at room temperature. Store leftovers tightly wrapped in the fridge for up to 4 days.