Puff pastry codfish parcels with leek and sultanas - Riberalves

Ingredients

• 2 Riberalves Cod Fillets
• 1 pack rectangular puff pastry
• milk q.b.
• 1 small onion
• 1 large leek
• 2 c. of soup filled with golden sultanas
• 200 ml of bechamel sauce
• Salt and black pepper q.b.