Whipping up this savory pie is a cinch when you keep frozen puff pastry on hand. Remember to use a very sharp knife to cut the pastry - if the edges of the dough are pressed together, it won't rise evenly.
Preheat oven to 425 degrees. Coat 12x8-inch baking dish with cooking spray.
Beat 4 eggs; stir in spinach, feta, scallions, and seasoning. Transfer to baking dish.
On lightly floured surface, roll puff pastry sheet into 13x10-inch rectangle. Cut into 3/4-inch-wide strips; brush with the 1 beaten egg. Arrange pastry in lattice over filling. Bake 25 minutes or until golden.