Step 1

Preheat oven to 375 degrees with racks in center and bottom third. On a lightly floured surface, roll out one disk of dough to a scant 1/8 inch thick (about 13 inches in diameter). Fit into a 9-inch pie dish. Roll remaining disk of dough on a lightly floured sheet of parchment to a scant 1/8 inch thick. Starting on right side, 2 inches from edge with a ruler held vertically, cut 2-inch slits with a paring knife into dough, spaced about 1 inch apart. Move ruler 1/2 inch to the left and continue making 2-inch slits, starting parallel to center of first set, so spaces alternate. Continue working across rest of dough, leaving a 2-inch border all around, then transfer parchment with dough to a baking sheet. Gently stretch dough horizontally to reveal grate pattern (if dough is too soft or breaking, refrigerate until pliable, about 10 minutes). Refrigerate pie dish and baking sheet with dough while making filling.

Step 2

Place cherries in a medium saucepan over medium heat; cover and cook, stirring occasionally, until cherries release their juices and come to a simmer, about 15 minutes.

Step 3

In a bowl, whisk together sugar and cornstarch. Pour mixture into pan with cherries; stir to combine. Bring to a simmer and cook, uncovered, stirring frequently, until juices thicken, 2 minutes more. Remove from heat.

Step 4

Peel, quarter, and core pears. Cut crosswise into 1/4-inch slices. Add to cherry mixture along with vanilla, spices, and salt; stir to combine. Let cool completely. Filling can be stored in an airtight container in refrigerator up to 1 day.

Step 5

Transfer filling to crust; dot with butter. Cover with lattice piece of dough. Pinch dough where top and bottom crusts meet. Trim excess to a 1-inch overhang; roll dough underto seal and crimp as desired (to create a rope effect, slash rolled edge witha paring knife on a diagonal). Freeze 30 minutes.

Step 6

Whisk egg with 1 teaspoon water, then brush over top of pie. Place a parchment-lined baking sheet on bottom rack of oven. Bake pie on center rack until golden brown and bubbling in center (if browning too quickly, tent with foil), about 1 hour, 30 minutes. Transfer to a wire rack and let cool completely, about 3 hours. Serve room-temperature.