Hortopita (Χορτόπιτα) is a wild-greens phyllo pie, and the honest framing is that it sits in this catalog as a savory hand pie rather than a sandwich in the strict sense: greens encased in thin pastry, cut into pieces and eaten out of hand. The angle is the horta itself, the foraged and field greens that give the pie its name. A hortopita is judged on the greens, their mix and their bitterness and how well they have been wilted and drained, far more than on richness, because unlike its cheese-pie relatives it leans green and lean.
The make runs in a clear order and most failures are moisture failures. A mix of greens, often wild and seasonal, is washed hard, wilted down, squeezed dry, and chopped; the squeezing is the step everything depends on, because wet greens steam the pastry into a gray soggy seam from the inside. The drained greens are dressed with olive oil, onion or spring onion, herbs like dill or fennel, and sometimes a small amount of feta, though many versions stay fully herb-and-green with no cheese at all. This filling is laid between sheets of thin phyllo, the layers brushed with olive oil, and the pie is baked until the top is deep gold and audibly crisp. Good hortopita shows a shatteringly crisp top and bottom crust with a dense, savory, faintly bitter green layer that holds together when a piece is lifted. The classic failures are underdrained greens that sog the base, phyllo brushed too sparingly so the layers go papery and dry instead of crisp, and a filling so thin or so wet that a cut slice slumps apart instead of standing.
It shifts by region and by what grows nearby, since the horta mix is whatever the season and the hillside offer, and by whether feta is included or left out for a leaner, often Lenten reading. Its richer cousins, the cheese pie and the meat pie built on the same phyllo principle, are distinct preparations and each deserves its own article rather than being crowded in here. The constant for hortopita is the discipline of the greens: pick a good bitter mix, wilt and wring it bone dry, layer the phyllo with enough oil to crisp, and bake it until both crusts crack.