Make the crust: Pulse the flour, shortening, granulated sugar and salt in a food processor until combined. Add the butter and pulse until it is in pea-size pieces. Drizzle in 2 tablespoons cold water and pulse until the dough just comes together. Turn out onto a piece of plastic wrap; use the plastic to help form the dough into a disk. Wrap tightly and refrigerate until firm, at least 1 hour or overnight. (The dough can be frozen for up to 2 months; thaw at room temperature.)
Roll out the dough into a 12-inch round on a lightly floured surface. Ease into a 9-inch springform pan, pressing it into the bottom and 2 inches up the side. Chill 30 minutes.
Preheat the oven to 350 degrees F. Line the crust with foil and fill with pie weights or dried beans. Bake until golden around the edge, about 20 minutes. Remove the foil and weights and continue baking until the crust is golden all over, 10 to 15 more minutes. Transfer to a rack and let cool completely.
Meanwhile, make the filling: Spread the walnuts on a baking sheet and toast in the oven until golden, 8 to 10 minutes; let cool. Pulse in a food processor with the butter, confectioners' sugar, egg, cinnamon and salt to form a paste; set aside.
Combine 2 cups water and the granulated sugar in a medium saucepan and bring to a simmer over medium-high heat. Peel the pear and cut into 3/4-inch chunks. Add to the saucepan and simmer until tender, 8 to 10 minutes. Drain, then spread the pear on paper towels and let cool completely.
Spread the walnut filling evenly in the cooled crust, then press the pear and chocolate chunks into the filling. Bake until the filling is puffed and golden and a toothpick inserted into the center comes out clean, 30 to 40 minutes. Transfer to a rack and let cool completely.