THAW phyllo dough according to package directions; PLACE oven rack in lower third position; PREHEAT oven to 425°F ; SELECT a 14 x 9 deep metal baking sheet pan; SPRAY inner baking sheet surface with non-stick cooking spray; INSERT and fit a large sheet of parchment paper (not waxed paper!) into sheet pan; PRESS parchment paper in firmly.
RINSE spinach and transfer into a large microwave-safe bowl containing 1/2 cup water; COVER bowl with a large plate; MICROWAVE on high power for 5 minutes. LET stand 1 minute; WEARING oven mitts, remove bowl from microwave; REMOVE plate from bowl; CAREFULLY drain spinach in colander placed in sink; PRESS spinach against colander to extract excess water; PLACE drained spinach on cutting board; COARSELY chop spinach; PLACE chopped spinach onto center of clean kitchen towel; SQUEEZE out as much moisture as possible into sink.
TRANSFER spinach into a large mixing bowl; ADD the remaining filling ingredients; STIR mixture until thoroughly combined.
LAY one sheet phyllo into baking dish, and brush thoroughly with melted butter; REPEAT procedure with 9 more phyllo sheets, brushing each with butter.
SPREAD spinach mixture evenly over phyllo, leaving a one-quarter inch border free on all sides.
COVER spinach with one phyllo sheet, brushing with butter; SPRINKLE buttered phyllo sheet with 2 tablespoons grated parmesan cheese; LAY another 2 sheets phyllo on top of cheese-sprinkled layer; BRUSH with butter (do not add cheese to the following two sheets); REPEAT with one more phyllo sheet.
PRESS layers gently with hands to release residual air pockets; SCORE the pie using a sharp knife through the top 3 phyllo layers into 9-12 equal pieces.
BAKE for 20-25 minutes, or until phyllo is golden brown and crispy; COOL pie at least 10 minutes.
LIFT out and slide parchment insert containing pie carefully onto a cutting surface; SLICE along scores, lifting pie from parchment with a sharp spatula before serving.