• Preheat: Preheat the oven to 375°F.

Crust

• Make pie crust: In a large bowl, stir together 2 1/2 cups cups flour and 1 teaspoon salt. Using a pastry cutter or large fork, cut 1 cup cold butter into the flour until it forms pea-sized crumbles. You'll want to work fast so the butter doesn't have time to warm up. You may also use a food processor for this step, if preferred.
• Add water: Adding 1 Tablespoon water at a time, stir until the dough comes together to form a ball. Stop adding water when this happens or you will end up with sticky dough.
• Chill dough: Wrap the dough in plastic wrap. Chill 1 hour.
• Press crust: Press crust on bottom of 10x15" baking sheet. Place in the refrigerator until ready to top. You want your dough to be cold before baking.

Crumb Topping

• Make crumb topping: Meanwhile, in a mixing bowl, combine 1 cup flour, 2/3 cups brown sugar, and 1 teaspoon cinnamon. Slowly drizzle the 1/2 cup butter into the bowl while stirring the crumbs with a fork. I like to start with 3-4 Tablespoons and add more as needed until the crumbs form. Do not over-mix (you do not want this to become like a dough). Set aside.

Filling

• Make apple filling: In a large bowl, combine 1 cup sugar, 1/3 cup flour, 1 1/2 teaspoons cinnamon and 1/4 teaspoon nutmeg. Add 8 apples, sliced, and toss until coated.
• Assemble pie: Add the sliced apples in even layers onto the pie crust, leaving excess juice in the bowl. Sprinkle the crumb topping over the entire pie.
• Bake pie: Bake for 45 minutes.
• Cool: Remove pie from oven and let cool for at least an hour before serving. Serve with vanilla ice cream, if desired.