Place one of the pie crusts into the bottom of a 9-inch pie dish.
In a large bowl, mix the apples, sugar, cinnamon, nutmeg, and flour.
Pour the apples into the prepared pie crust.
Place top crust onto the apples. Cut off the excess crust with a knife or kitchen shears. Pinch edges of crust together to seal. If you want to be fancy, you can cut the top crusts into strips and weave them into a lattice.
Mix the egg white and the water in a small bowl. Brush liberally over the top crust. Sprinkle the sparkling sugar onto the crust. Place the pie on a foil-lined cookie sheet to protect the oven from spillovers.
Cover the edges of the crust with a pie crust shield or aluminum foil. Bake at 375°F for 25 minutes. Remove the pie shield or foil and bake for another 20-25 minutes until the crust is browned and the filling is bubbly.
Store-bought pie crusts keep well in the freezer. Defrost in the fridge overnight, or leave it out on the counter for a few hours before you want to put your pie together. This way you can toss together a quick pie anytime.