Preheat oven to 400 degrees. Prepare a large baking sheet by lining with parchment paper. Set aside. Peel, core, and dice pears. Add to a medium bowl with butterscotch sauce and ground cinnamon. Toss with a spoon to combine. Set aside.
Unwrap one sheet of puff pastry and roll out into a 10x10 square. Cut into 4 even squares. Add 2 tablespoons of pear filling to the center of each square. Brush the edges of each square with water and fold one corner over the center to form a sealed triangle. Pinch the edges of the triangle shut and seal with a fork. Place sealed turnovers on the prepared baking sheet and place in the refrigerator while you repeat the process with the other sheet of puff pastry.
Create egg wash by beating 1 large egg with 1 teaspoon of water. Brush each turnover with egg wash. Sprinkle each turnover with coarse sugar. Cut 3 small slits in the center of each turnover to help the steam release while baking. Chill the pastries in the freezer for 10 minutes.
Bake turnovers in preheated oven for 23-25 minutes or until the centers of the pastry have browned. Remove from the oven and let cool for 10 minutes before eating.