You'll also need -20ºC rozen pastry sheet, cut into a 8 cm X 20 cm rectangle and some melted butter. Preheat the oven to 375 degrees. In a medium bowl, hand mix the salmon, cream cheese, Feta cheese, egg, capers, parsle, and scallions. Roll out the pastry sheet to double its size. Liberally brush it with melted butter. Spread the salmon mixture over the sheet. Roll up, jelly-roll style, folding the ends in to seal. Brush the top of the roll with melted butter and sprinkle with poppy seeds. Make 1 cm deep diagonal slashes across the roll to allow steam to escape. Bake the roll for 20 to 30 minutes or until golden. Serve warm.