1. Preheat oven to 400 degrees Fahrenheit. Line two baking sheets with Gefen Parchment Paper; set aside.
2. Place thawed puff pastry on a floured surface. With a rolling pin, roll out so the pastry is an even, thin layer, about one-eighth-inch thick. Repeat with remaining squares.
3. Place a few slices of apple from the pie filling in the bottom right hand corner of each square, leaving a small border.
4. Brush egg wash onto the edges of each square, then fold the dough over, making a triangle. Use a fork to crimp the edges, stretching the dough over the fruit as needed. Just be gentle, so the pastry does not break.
5. Brush additional egg wash over bourekas; sprinkle with sugar.
6. Place bourekas onto prepared baking sheets; bake for 30 minutes, or until pastry is golden brown.
7. Remove from the oven and allow to cool.