Preheat the oven to 375°F and line a baking sheet with parchment paper.
In a mixing bowl, combine the diced pears, chopped walnuts, brown sugar, cinnamon, nutmeg, and lemon juice until the fruit is evenly coated.
Unroll the pie dough sheets on a lightly floured surface and cut out eight 4-inch circles using a round cutter or glass.
Spoon about 2 tablespoons of the pear filling onto the center of four circles, leaving a small border around the edge.
Top each filled circle with a second dough circle, press the edges together with a fork to seal, and cut two small slits in the top of each pie.
Brush the tops with the beaten egg and sprinkle evenly with granulated sugar.
Place the hand pies on the prepared baking sheet and bake for 20 to 25 minutes until the crust is golden brown.
Remove from the oven and let cool on the sheet for 5 minutes before transferring to a wire rack.