Spanokopita (greek Spinach Pie)

If you are using fresh spinach, wash the spinach and remove the tough
stems. Place in a large bowl and sprinkle heavily with salt. Rub the salt
into the leaves by taking them up, a bunch at a time, and rubbing them
between your hands; the volume of the spinach will decrease before your
eyes. Tear the spinach up as you do this. Rinse the salt off thoroughly
and dry the spinach, squeezing it in bunches in a towel. (If you are using
frozen spinach, just let it thaw and squeeze out excess moisture).

Saute the onion and mushrooms in a little olive oil and butter with the
garlic and salt and pepper to taste. When both the onions and mushrooms
are tender, remove from the heat.

Beat the eggs in a large bowl and crumble in the feta cheese; add the
Parmesan, then the spinach, onions, and mushrooms. Stir in the parsley,
oregano, rosemary, some freshly ground pepper, and a little salt (remember
that the feta is very salty).

Preheat the oven to 375 degrees.

Melt the butter and brush a 2-quart or 3-quart oblong baking pan with it.
Spread your filo dough out flat next to the pan. Take a sheet and lay it in
the pan, letting the edges come out over the pan. Take another sheet and
lay it on top of the first, not directly but in such a way that its edges
extend over different parts of the pan. Brush with butter. Continue to
layer the sheets of filo, brushing every other one with butter and turning
each one slightly so that the edges fan out over the sides of the pan,
until you have about eight sheets left.

Now spread the spinach mixture evenly over the filo dough in the pan,
pushing it into the corners. Take the edges of the filo and fold them in
over the spinach mixture.

Take the remaining sheets of filo and layer them one by one over the
spinach mixture, again brushing every other sheet with butter, but this
time pushing the edges down into the sides of the pan. It is difficult to
do this neatly; just rumple the edges down into the sides of the pan (they
will form a nice crisp edge after baking). Brush the top of the spanokopita
with butter and make +-inch-deep diagonal slashes across it with a sharp
knife.

Bake for 50 minutes, until the crust is puffed up and golden; it will
shrink from the sides of the pan. Cut into squares or diamond shapes and
serve immediately.