1. Preheat oven to 200°C (400°F). 
2. Cut each sheet of puff pastry into 6 squares measuring about 8 cm x 8 cm (3 in. x 3 in.). 
3. Heat oil in a skillet over medium-high heat and wilt spinach. Set aside. 
4. Spoon about 60 mL (¼ cup) bechamel sauce, reserved spinach, and swiss cheese onto each pastry square. 
5. Fold corners into the middle of each square and seal well. 
6. Beat egg yolk with water and brush onto dough. Season with freshly ground pepper. 
7. Bake in the oven for 25 to 30 minutes, until pastry is flaky and golden. 

Chef’s secret

Perfect for finishing off leftover chicken bechamel sauce, this recipe makes a good brunch dish.