Preheat oven to 450 degrees F (230 degrees C). Place a baking sheet on the bottom oven rack.
Combine sugar, flour, salt, cinnamon, and lemon zest in mixing bowl. Roll out half the pastry and line a 9-inch pie pan.
Arrange pear slices in layers in the pastry-lined pan, sprinkling the sugar mixture over each layer. Dot with butter and sprinkle with lemon juice.
Roll out remaining dough for the top crust. Use your finger dipped in a small bowl of water to moisten the rim of the bottom crust. Place top crust over filling, and trim edge using kitchen shears or a sharp paring knife. Fold edge under bottom crust, pressing to seal. Flute edge. Cut slits in top crust to allow steam to escape.
Bake in the preheated oven on the baking sheet for 10 minutes. Reduce oven temperature to 350 degrees F (175 degrees C), and bake until crust is golden brown and filling is bubbly, 35 to 40 minutes longer. Allow to cool several hours before serving.
