Fresh blueberries are enhanced with lemon and cinnamon for the filling of this beautifully decorated pie.
Pate Brisee: Pulse flour, salt, and sugar in a food processor to combine. Pulse in butter until mixture resembles coarse meal, about 10 seconds. With machine running, add 1/2 cup ice water in a slow, steady stream, just until dough holds together. To test, squeeze a small amount together; if it is crumbly, add up to 1/4 cup more ice water, a little at a time. Do not process more than 30 seconds.
Turn out dough onto a clean surface and divide into three equal pieces. Place each on a piece of plastic, flatten into disks, and wrap tightly. Refrigerate at least 1 hour before using. Dough may be stored, frozen, up to 1 month.
Filling: Preheat oven to 425 degrees with rack in center. Line a rimmed baking sheet with foil and place on rack to preheat.
In a medium bowl, gently toss together blueberries, lemon zest and juice, sugar, cornstarch, salt, cinnamon, and butter.
On a lightly floured surface, roll out one disk of dough to a 13-inch round; fit into a 9-inch pie dish. Refrigerate while making lattice. Roll out a second disk of dough to an 11-inch square. Trim edges, then cut square into ten 1-inch-wide strips; repeat with remaining disk.
Assemble lattice on a parchment-lined unrimmed baking sheet. You will be alternating between double strips of dough and a single strip to create this pattern. Lay two strips, touching one another, diagonally across the center of the parchment. Lay another strip on top of the two strips, going diagonally in the opposite direction. Continue weaving, following the pattern of double and single strips in opposite diagonal directions. You will need to fold back double strips as you work to lay the single strips, then unfold them to weave a lattice pattern. You may have some dough strips left over. Transfer sheet to freezer until lattice is well chilled, about 30 minutes.
Transfer blueberry mixture to prepared pie dish. Brush edges of crust with egg wash. Place chilled lattice over filling; press edges to seal with bottom crust. Using kitchen shears, trim dough to a 1-inch overhang. Tuck overhang under so edges are flush with rim. Brush lattice with egg wash and sprinkle with sanding sugar.
Bake on preheated baking sheet 20 minutes, then reduce oven temperature to 375 degrees and continue baking until filling is bubbling and crust is evenly browned (if browning too quickly, tent edges with foil), 60 to 75 minutes. Transfer to a wire rack and let cool completely.