Butter 6 whole filo sheets and overlap each in a buttered 9 x 13 pan so part of filo laps over edges of pan. Spread on all of filling. Flip edges of filo over to cover filling. Cover with 6 more buttered filo sheets and overlap and cover as before. Work quickly so filo doesn't dry out. Score 2/3rds through filo prior to baking. Bake in a 350 oven for 20 to 30 minutes or golden.