Roll out the puff pastry into 1/4-inch thickness. Cut into four (3 by 12-inch) pieces. Dock the dough all over. Bake for 18 to 20 minutes or until golden brown in color. Transfer to a baking rack to cool. Reserve 2 puff pastry strips. Cut each of the remaining two into 6 equal pieces. Reserve.
In a bowl, soak gelatin leaves with cold water to soften.
In a medium bowl, combine the eggs, sugar and vanilla scrapings. Cook over a double-boiler, whisking all the while, until mixture begins to thicken. Remove from heat and stir in the gelatin. Carefully fold the whipped cream into the egg mixture. Allow to cool and thicken for 15 minutes.
To assemble: Spread 1/3 cup of raspberry marmalade on top of the 2 (12-inch) puff pastry pieces. Top raspberry marmalade with the cream mixture. Cover with cut pieces of puff pastry and refrigerate at least 1 hour before service.
To serve: Sprinkle with powdered sugar. Serve immediately.