Melt the butter in a large Dutch oven over medium heat. Add the apple slices, brown sugar, sugar, and lemon juice. Stir with a wooden spoon occasionally, making sure they do not burn.
Dissolve the cornstarch in about ¼ cup of cold water. Stir to combine.
Cook the apples over medium heat until they are slightly softened, 12-15 minutes. You do not want to fully cook them, as they will continue to cook as the pie bakes.
Pour in the cornstarch mixture once they are almost done and let cook to thicken the apples and juice. Cornstarch needs brought to a brief simmer in order to properly thicken.
Remove from the heat and add the cinnamon, nutmeg and stir to combine. Let the pie filling cool completely.
Add the pie filling to a glass bowl, cover with plastic wrap and refrigerate overnight if needed.
Assemble & bake the apple pie
On a lightly floured work surface, roll out the bottom crust slightly larger in diameter than your baking dish. Gently place the pie crust into a 9 or 9 ½-inch pie dish lightly, using your fingers. Use kitchen shears to trim the edges of the crust, to about ½-inch past the pan rim.
Add the cooled or chilled apple pie filling to the unbaked pie shell.
Roll out the top crust. Place the top pie crust over the seasoned apples. Or weave a lattice crust.
Trim the edges of pie crust with kitchen shears and roll under the crust. Crimp with your fingers or press with a fork.
Use a sharp knife to cut vent holes in the center of the pie.
Brush with an egg wash and sprinkle with granulated sugar. Place in a preheated 400 degree F oven for about 1 hour.
The crust will be golden brown and the filling bubbling up near the vent holes and edges of the crust. Let cool for at least an hour before slicing. This will allow the pie filling to set.
Notes
Place the pie on a half sheet pan lined with parchment paper. This will help collect any juices that may spill over while it bakes. This helps for easy cleanup!Test if apples are cooked – Use a fork or a sharp knife inserted through the vent holes to test the texture of the pie. (My mom always liked the apples to be slightly soft, so that’s the way we prefer our apple pie.) If you like your apples a little more firm, you can bake for less time.Cool before slicing – Let your apple pie cool to room temperature before slicing. This will help the filling set and thicken.