Thaw frozen pastry sheets at room temperature until soft- approximately 30 minutes.
Mix 1 egg and water in a small bowl to create an egg wash for the pastry.
Mix remaining 2 eggs, feta cheese, spinach, onion, garlic salt and parsley.
Unfold pastry on floured surface. Roll each sheet into 12 inch square and cut each sheet into 16 squares. Place 1 tablespoon of the spinach mixture in center of each square. Brush edges of squares with egg mixture. Fold squares to form triangles. Press edges to seal. Brush with egg mixture to create shine.