01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper and set aside.
02 - Melt butter in a skillet over medium heat. Add diced pears, brown sugar, cinnamon, nutmeg, and lemon juice. Cook for 5 to 7 minutes, stirring occasionally, until the pears are tender and the mixture has thickened. Remove from heat and let cool for 10 minutes.
03 - On a lightly floured surface, roll out the puff pastry if needed. Cut into 6 equal rectangles or squares.
04 - Place a generous spoonful of pear filling onto one half of each pastry square. Fold the pastry over to enclose the filling, forming a triangle or rectangle. Press the edges firmly with a fork to seal.
05 - Transfer the filled pastries to the prepared baking sheet. Brush the tops evenly with beaten egg and sprinkle with granulated sugar.
06 - Bake for 18 to 22 minutes until the pastries are puffed and golden brown.
07 - Allow pastries to cool slightly before serving. Serve warm on its own or paired with a scoop of vanilla ice cream.