Preheat oven to 400°F and line a baking sheet with parchment paper.
Drain spinach of any excess water. In a medium bowl, stir together spinach, ricotta cheese, mozzarella cheese, garlic, shallot and salt.
Unfold sheets of puff pastry. Cut each sheet into four equal squares. Place 2 Tablespoons of spinach mixture into the center of each pastry square. Fold each pastry square diagonally over spinach. Pinch edges of dough together with a fork. Brush the tops and sides of each turnover with the beaten egg.
Place each turnover on the lined baking sheet. Bake 16-18 minutes or until pastry is golden brown.