Join the two sheets of puff pastry in the package by their short edges to make a long rectangle. Brush water along edges and press down gently with fingertips to seal.
Mix apples, cinnamon, brown sugar, almonds and butterscotch chips, and spoon onto long edge of pastry.
Fold one side of pastry over the mixture and roll into a long streudel. Make sure to seal at both ends. Brush pastry with melted butter and make two-inch diagonal slits the length of the strudel with a sharp knife.
Bake on parchment paper at 375 F [conversion] for 30–35 minutes. Sprinkle sugar over top halfway through cooking.