1. Preheat the oven to 400 degrees.
2. Spray a baking sheet with baking spray.
3. Unfold 1 sheet of puff pastry and carefully wrap it around the cheese.
4. Beat the egg with the water and brush it on the seam of the pastry. Place seam side down on a baking sheet then brush the top with the egg mixture.
5. Bake for 25 minutes. Remove from oven and immediately spread a thin layer of jam on top if using.
6. Let cool for 5 minutes before serving with crackers.