Puff Pastry Spinach and Feta Pie (Spanakopita)

Steps

1. Thaw puff pastry sheets in the fridge overnight, then let sit at room temperature for 45 minutes.
2. Wash spinach and chop roughly; if using frozen spinach, thaw and squeeze out excess water.
3. Heat a little olive oil in a pan and sauté the minced spring onions until soft.
4. Add the spinach and cook until wilted and any liquid has evaporated. Remove from heat and let cool slightly.
5. In a saucepan, melt the butter over medium heat, then whisk in the flour to form a paste and cook for 1-2 minutes.
6. Gradually whisk in the milk, stirring constantly until the sauce thickens into a smooth béchamel.
7. Remove the béchamel from heat and let cool slightly, then whisk in the eggs one at a time.
8. Stir in the crumbled feta and minced dill (or spearmint) until combined.
9. Fold the spinach and spring onion mixture into the béchamel filling and mix well.
10. Preheat the oven to 180°C (350°F).
11. Brush a baking pan with olive oil and lay one sheet of puff pastry in the bottom, letting edges hang over the sides.
12. Spread the spinach and feta filling evenly over the pastry.
13. Cover with the second puff pastry sheet, folding and sealing the overhanging edges together.
14. Brush the top with egg yolk for a golden finish.
15. Score the top lightly into serving pieces without cutting all the way through.
16. Bake for about 75 minutes, or until the pastry is puffed and golden brown.
17. Let cool slightly before cutting into pieces and serving.