Preheat oven to 350 degrees Fahrenheit. Line a rimmed baking sheet with parchment paper and set aside.
Lightly flour your work surface and unfold 1 sheet of puff pastry on it. Roll out the puff pastry to a rectangle that's roughly 16"x10".
Transfer dough to the baking sheet.
In a medium bowl, toss the pear slices, walnuts, maple sugar, and maple syrup, coating evenly.
Arrange tossed pears and walnuts over the surface of the puff pastry, leaving 1/2-1 inch around the edges free.
Sprinkle Cashel Blue evenly over the surface.
Fold the edges over, pinching the corners where the sides come together.
Bake for 22 minutes, or until lightly browned.
Remove to a wire rack to cool before serving.