Cook the filling. Add the frozen cherries, vanilla (scrapings and bean), sugar, and salt to a 5-quart pot over medium heat, and stir to coat the cherries in sugar. Cover the pot and cook until the sugar is fully dissolved and the cherries are at a simmer, about 10 to 12 minutes, stirring occasionally. Stir in the cornstarch slurry, and cook until thickened, about 1 to 3 minutes, stirring constantly. Remove from the heat and stir in the almond extract.
Cool (3-4 hours at room temperature) and then chill the filling (12-24 hours in the fridge). Cool to room temperature (about 3 to 4 hours), and then refrigerate to chill (12 to 24 hours). (TIP: After chilling overnight, the filling will have thickened to the perfect consistency. See Notes below.) Remove and discard the vanilla bean.
Make and Chill the Pie Dough:
Make the dough. Whisk together the flour and salt in a large bowl. Cut in the butter with a fork, a pastry cutter, 2 butter knives, or your fingertips. It should look crumbly, with some pieces of butter the size of small peas. Drizzle the water in a little at a time, mixing as you go (you can use a fork to mix, but mixing with your fingertips works best here). Add just enough water so it comes together to form a ball of dough (you may need more or less water).
Chill the dough (at least 30 minutes or up to 3 days in the fridge). Divide the dough into 2 equal parts. Roll each into a ball, flatten each ball slightly into a disk, wrap them in plastic wrap, and refrigerate until chilled, about 30 minutes.
Assemble the Pie:
Prep. Preheat the oven to 425F. Position a rack in the center of the oven to bake the pie on. Get out a standard 9-inch pie pan. If you don't have a pie drip catcher, put a piece of aluminum foil under the pie plate to catch any drips as it bakes.
Roll out the first disk of dough (bottom crust). Place 1 disk of dough onto a floured work surface. Working from the center out, roll the dough out to a circle about 11 to 12 inches in diameter. Fold the dough over onto itself, pick it up, and transfer it to a pie plate. Unfold the dough and push it into the bottom and up the sides of the pie plate. Use a fork to poke several holes in the bottom of the pie crust.
Add the filling. Transfer the cooled cherry filling into the pie crust and spread it out evenly. Pop this into the fridge while you roll out the second disk of dough.
Roll out the second disk of dough (top crust; lattice or regular). Roll out the second disk of dough to a circle about 10 inches in diameter the same way you rolled out the first disk of dough. To make a regular crust top, place the circle of dough onto the cherry filling. Tuck the outside of the dough under, and use your fingers or a fork to flute the edges. Cut 6 to 8 slits in the top of the crust. To make a lattice crust top, cut the dough into strips about 1 inch wide. Lay 4 to 6 strips on top of the pie spaced evenly apart. Starting at the center, fold back every other strip and place a strip across so it looks like it was weaved in, continuing until the lattice is completed. Trim off the excess dough from the strips and tuck the strips under, crimping the edges if desired.
Egg wash. For the egg wash, whisk together the egg and water. Lightly brush it on the dough.
Bake the Pie:
Bake at 400F for 20 minutes, then reduce the heat to 375F and bake until the pie is done, about another 40 to 60 minutes. The pie is done when the top crust is golden brown and the filling is bubbling in the center. If you’re using a glass pie plate, you can check the bottom to make sure the bottom crust is golden and doesn’t look raw. (TIP: At the 1-hour mark, check the pie every 10 minutes; if the top is starting to brown too quickly, cover it with foil and continue baking until done.)
Cool:
To allow the filling to properly set, let the pie cool until it’s at least lukewarm (about 3 to 4 hours) before slicing.
Notes
Pie Pan: Use a glass pie plate if possible. This allows you to check the pie for doneness from the bottom as well as the top (the bottom crust should be golden too). No soggy bottoms here!
Cherry Pie Filling: This makes about 1 liter of cherry pie filling. We use the whole amount for this pie.
Don’t Add More Cornstarch to Make the Filling Thicker: It will thicken perfectly as it chills in the fridge overnight (12 to 24 hours). If you add more cornstarch, yes the filling will be thicker, but you run the risk of the filling turning gluey, especially because we're baking it into pie (which thickens the filling even more).
Recipe Yield, Serving Size, and Nutritional Information: This recipe makes one 9-inch pie, which is enough for 8 large slices, or up to 12 smaller slices. The nutritional information is based on it making 8 servings.
Storage:
Filling: Cool to room temperature, and then store homemade cherry pie filling in an airtight container in the fridge for up to 5 days or in the freezer for up to 6 months. After freezing, thaw to room temperature before using it to make pie.
Pie: After baking, cool the pie to room temperature. After that, you can store it at room temperature for up to 2 days, in the fridge for up to 1 week, or in the freezer for up to 2 months.
Reheating Pie: Skip the microwave (which can turn the crust rubbery), and reheat a slice of pie on a baking tray or other oven-safe dish in a 350F oven until warm. You'll be rewarded with crispy crust!