Grease a 9” x 13” pan with oil or oil spray. Lay down 8 sheets of filo dough, brushing or spraying with oil in between each layer.
Allow spinach to thaw and squeeze out water. Set aside.
Heat 1 tsp. oil in a pan. Meanwhile, dice onion and sauté until translucent. Turn off the heat and mix in the spinach.
Mix in the cottage cheese, feta cheese, parmesan cheese, salt, pepper, and nutmeg into the spinach mixture.
Spread mixture out in the pan, and cover with remaining filo dough. Spray with oil spray between each layer.
(Optional) Pre-cut squares. Using a sharp knife, slice into 12 squares taking care not to slice the bottom filo dough. This will help keep the pastry on each square together.
Bake 45 minutes at 375°F or until top is golden brown. Remove from oven and let stand for 5 minutes. Cut into squares and serve.