Poach the pears. Simmer the sugar and water until the sugar dissolves. Remove from the heat. Stir in the pears and wine. Let cool. Chill for at least 12 hours. Drain and dry the pears completely. Set aside.
Make the dough. In a large bowl, mix together the flour, egg and egg yolk, and salt. In a separate bowl combine the yeast and warm milk and stir until the yeast dissolves. Add to the flour mixture. Beat in the butter and sugar. Knead into a smooth dough, about 5 minutes. Cover and let rest in the refrigerator for at least 2 hours.
On a lightly floured surface, roll the dough into a 20-inch square about ¼ inch thick. Cut into sixteen 5 by 5-inch squares.
Make the cheese filling. Bring the milk to a boil in a heavy-bottomed saucepan. Set aside. In a heatproof bowl, mix the sugar, cornstarch, and egg yolks. Pour some milk into the bowl, then pour this mixture back into the remaining milk in the saucepan and bring to a boil again, for 30 seconds, while stirring. Let the mixture cool to room temperature and mix in the mascarpone.
Preheat the oven to 350 degrees F. Line 2 baking sheets with parchment paper.
Spread a thick layer of the cheese mixture across the end of the piece of dough. Sprinkle with pears and chopped chocolate. Fold the other half of the dough over the filling and pinch all sides to seal.
Place the pockets on the prepared baking sheets. Mix the yolk and water together to create an egg wash. Lightly brush the pockets with the egg wash. Bake until golden brown, about 25 minutes, then sprinkle with confectioner’s sugar. Serve hot.