Preheat your oven to 375 degrees Fahrenheit. Lightly grease a pie dish or tart pan.

If using frozen spinach, thaw and squeeze out excess moisture using a clean kitchen towel.

In a large skillet over medium heat, add olive oil. Sauté the diced onion until translucent, about 5 minutes. Add minced garlic and cook for 1 more minute.

In a large mixing bowl, combine the spinach, sautéed onions, garlic, crumbled feta, and ricotta. Whisk the eggs in a separate bowl and fold into the mixture. Add chopped dill, parsley, nutmeg, salt, and black pepper. Stir until well combined.

Line the prepared pie dish with one sheet of pie crust or puff pastry.

Pour the spinach mixture into the crust, spreading evenly. Top with the second crust sheet. Pinch edges to seal and cut vents in the top. Optional: brush with egg wash for a golden shine.

Bake in the preheated oven for 35-45 minutes, until the crust is deep golden brown and the filling is set.

Let the pie cool for 10-15 minutes before slicing into wedges.