Grease 8 cream horn metal cones. Cut the puff pastry into 1/2-inch wide strips. Starting at the point of the cone, wind the pastry around the cone, overlapping the layers slightly to cover the cone with a spiral of pastry. Freeze in an airtight container.
Preheat oven to 400 degrees F.
When ready to bake, whisk the egg with the water and lightly brush the pastry with the egg wash. Shake powdered sugar all over the surfaces and place them, seam side down on a parchment paper lined sheet pan. Bake for about 20 minutes or until golden brown. Let cool on the cones. Then remove and fill the cornucopias.
Whip the cream with the 1 tablespoon sugar until stiff, then chill it. Cut up the fruit. If desired, roll the blueberries in gold leaf to guild them. Pipe whipped cream into the pastry to fill in, then place it on a dessert plate. Garnish the cornucopia with cascading cut up fruit, then dust with powdered sugar.
Notes about the recipe: You can also fill these with custard and fruit.