Preheat the oven to 180°C.
Roll out the rectangular puff pastry sheet.
Mix the ricotta with the cooked and well-drained spinach.
Spread the filling over the puff pastry and close to form pockets.
Brush the pockets with the egg yolk mixed with milk.
Add the seeds if desired.
Bake for about 30-35 minutes until golden brown.
Recipe ideal for an aperitif or a light dinner.
Italia, Emilia Romagna