In a medium skillet, heat oil over medium heat. Add onions and salt. Cook, stirring occasionally, until softened, 4 to 5 minutes. Add crushed garlic and cook for about 30 seconds. Remove from heat
In a large bowl, stir together cream cheese and 1 egg. Stir in garlic-onion mixture, spinach, feta, lemon zest, black pepper and paprika.
Grease 9 cups of a muffin tin with cooking spray. Cut the pastry sheet into 9 squares. press each square into the bottom of the muffin cups. Add spinach filling evenly onto the pastry cups. Fold in pastry corners to meet in the center over the filling and pinch together. Refrigerate for 30 minutes (or freeze for 15 minutes).
Preheat the oven to 400F .Beat an egg in a small bowl with 1 teaspoon water and brush on top of the chilled pastry. Bake for 25 minute or until puffed and golden.