Scoop the chilled cherry filling into the crust. Make sure that the filling is spread evenly; it shouldn’t be mounded, with the center higher than the sides. You want the filling to touch the edges of the pan.
Lay out 4-5 strips parallel to each other across the top of the filled pie, leaving some space between each strip.
Fold back every other strip most of the way, then lay another strip perpendicular to the folded-back strips. Unfold the folded strips over the perpendicular strip. Fold back the alternate strips that were not folded the first time, lay down another perpendicular strip, and unfold the strips again. Repeat this process until the entire pie is covered in a lattice pattern.
Use scissors to trim any dough that’s hanging more than 1” off the sides of the pan.
Fold the overhang up and towards the center of the pie, which will tuck the ends of the strips into the overhang.
Press to seal. I formed somewhat of a thick and tall edge around the rim to prevent pie filling from boiling over. I even used some of the extra dough from the bottom crust and the cut-off overhang to help with that.
Crimp the sides if you'd like.
Chill the whole pie, uncovered, for 30 minutes before baking. While it’s chilling, place a baking sheet that’s big enough to catch any spillage in the lower third of the oven on the rack. Preheat the oven to 425 °F (218 °C). Mine takes 10 minutes to reach that temperature, so I start preheating the oven 20 minutes after I put the pie in the fridge.
After 30 minutes of chilling, whisk together the egg and water in a small bowl. Brush the lattice and the edges of the crust with the egg wash. Sprinkle the coarse sugar over the lattice crust.
1 large egg, 1 tablespoon water, 1 tablespoon raw cane sugar
Place the chilled pie on the hot baking sheet in the preheated oven.