Preheat oven to 400º.

Flour a clean work surface and roll first sheet of puff pastry into a 12-inch square.  Cut into 4 equal squares. Spread 2 tbsp Mascarpone or Cream Cheese onto one half of each square, then top with a heaping 2 tbsp cherry pie filling.  Fold pastry over the filling to make triangles.  Press the edges together firmly to seal, then crimp between fingers or press with a fork as desired.

Using a sharp knife, make two small slits in tops of turnovers (these steam vents will prevent the seal from breaking during baking).  Brush tops with the egg wash and arrange on a parchment-lined baking sheet.  Bake 15 minutes, or until golden brown and puffed.  Cool on wire rack for 10 minutes.