Set aside a 9-inch pie plate and preheat the oven to 425°F.

Melt the butter in a large pot over medium-low heat.

Add the apples, brown sugar, flour, cinnamon, lemon juice, and salt. Stir together and cook, stirring occasionally, until the apples soften, about 8 to 10 minutes. Remove from the heat and set aside to cool.

Meanwhile, divide the prepared pie dough in half and lightly flour a work surface.

Roll one disc of dough out to around 1/8-inch thick, making it a bit larger than your pie plate. Transfer the rolled sheet of dough into the pie plate.

Make the egg wash by whisking together the egg and water in a small bowl. Set aside.

Transfer the cooled cooked pie filling into the prepared crust.

Roll the other disc of pie dough out and place it on top of the pie, or cut into strips and braid the top layer, cutting vents if not braiding.

Trim the excess dough and crimp the edges to seal.

Brush the top with the egg wash and sprinkle with coarse sugar, if desired.

Bake for 15 minutes, then reduce the temperature to 350°F and continue baking for about 40 minutes until golden brown and filling bubbles.

Set aside to cool before serving.

Serve warm or at room temperature, optionally with vanilla ice cream or whipped cream.