Unfold puff pastry; cut into six rectangles. Place on a greased baking sheet. Spread 1 tablespoon Nutella over half of a rectangle; fold dough over filling. Press edges with a fork to seal. Repeat for remaining pastries. Brush with egg; prick tops with a fork.
Bake at 400° for 10-14 minutes or until puffy and golden brown. Sprinkle with confectioners' sugar if desired. Serve warm. Yield: 6 servings.