Wash and drain the chopped spinach very well. Spinach should be dry.
In a large skillet heat 6-7 tablespoons of olive oil and sauté the leeks and green onions until softened. Remove from heat.
In a large bowl add eggs, feta cheese and dill and mix well. Add the onion mixture and spinach, season with salt and pepper and mix until combined.
Lightly grease a 10×13 rectangular pan with olive oil.
Layer about 5 sheets on the bottom of the pan, making sure to lightly brush each sheet with olive oil (if using pastry fillo dough, you will use approximately 10 sheets). The pastry sheets will overlap the sides of the pan. Add the spinach mixture in an even layer. Turn in the overhanging pastry sheets toward the middle of the pan and lightly brush the layers with olive oil.
Continue layering the remaing sheets of fillo over the mixture remembering to lightly brush each pastry sheet with olive oil until all pastry sheets have been used. Brush the top sheet of the pie with olive oil. Tuck overhanging dough into pan to seal filling. Cut the pie in even strips lengthwise and bake in pre-heated 350 degree oven for approximately 30 minutes or until golden brown.
Cut into squares, serve and enjoy!