You'll be amazed by how much fresh spinach goes into this "spanakopita". Choose spinach with bright, full leaves because that's the flavor underlying the fresh dill, fresh parsley, and feta cheese. The feta is the other flavor you'll want to choose with care. I think French feta cheeses are too mild--and don't even get me started on Danish fetas, which are made from cow's milk and taste altogether different from Greek fetas. Go to a cheese market and taste Greek fetas. Choose a feta with some flavor; a delicate cheese will be lost beneath the spinach and dill. Rice in "spanakopita" is somewhat unusual, but just a little rice, toasted lightly in olive oil, adds wonderful texture to the filling. Don't hesitate to make this even if you're cooking just for two or four people. It keeps well refrigerated for several days, and actually packs up nicely for brown-bag lunches.
1. Preheat the oven to 350°F.
2. Heat the 1/2 cup olive oil in a stockpot over medium-high heat. Add the onions and sauté until lightly browned. Add the rice and stir until each grain is coated with oil, 2 to 3 minutes. Add the spinach in 5 small batches, folding the raw leaves under with a spoon as you add each batch. With each of the first 4 batches of spinach, add 1/2 teaspoon salt; add 1/4 teaspoon salt with the fifth and final batch. Allow each batch to wilt down before you add more spinach.
3. When all of the spinach is wilted, stir in the scallions, parsley, and dill. Strain off the liquid from the pot and let the mixture cool. (If you spread it out on a baking sheet, it will cool faster.) Once the mixture is cool, add the feta and pepper.
4. Brush a 9-by-13-by-2-inch baking dish with olive oil. Line the bottom of the dish with half of the phyllo sheets (10 to 12 sheets), layering them one at a time; press smooth, gently pressing the dough into the corners of the dish, and brush each sheet with olive oil before adding the next sheet. Allow any excess to come up the sides of the dish. Keep the stack of phyllo you're not working with covered with a damp kitchen towel.
5. Smooth the top sheet of phyllo and brush with olive oil. Spread the spinach filling evenly over the top. Cover with the remaining sheets of phyllo, again gently smoothing and brushing each sheet with olive oil before adding another. Brush the top with olive oil and trim the dough around the edges of the dish with a knife or scissors. With a very sharp knife, score the top into 12 squares, taking care not to cut more than the top layer or two of phyllo. Bake until the top is golden brown, about 40 minutes. Let cool, then cut along the score lines and serve.