Combine flour, salt, and sugar in a large bowl, then cut cold butter into pea-sized pieces throughout. Work quickly using a pastry cutter or your fingertips, creating a crumbly mixture within 3-4 minutes. Add ice water one tablespoon at a time, stirring gently until dough just comes together without becoming wet or sticky.

Form dough into two disks, wrap in plastic wrap, and refrigerate for at least 30 minutes while you prep the filling. This resting period allows gluten to relax, preventing shrinkage during baking and ensuring the crust stays tender and flaky.

Toss sliced apples with both sugars, flour, cinnamon, nutmeg, and lemon juice in a separate bowl, letting it sit for 10 minutes. This resting time allows the filling to release its juices naturally, creating that signature saucy texture that makes this thanksgiving apple pie crowd favorite so special.

Preheat your oven to 375°F and roll out the first dough disk on a floured surface to about 1/8-inch thickness. Transfer carefully to a 9-inch pie dish, allowing edges to overhang slightly, then add the apple filling and smooth the top layer evenly.

Roll out the second disk and place it over the filling, then crimp edges using your fingers or a fork to seal completely. Whisk together egg and water, brush the entire top surface, then cut three small vents to allow steam to escape during baking.

Bake for 50 minutes until the crust turns deep golden-brown and you can see filling bubbling slightly through the vents. If edges brown too quickly, cover loosely with foil during the final 15 minutes to prevent burning.

Cool on a wire rack for at least 20 minutes before slicing, allowing the filling to set properly. This cooling step ensures clean, beautiful slices rather than filling that runs all over the plate.