• Preheat the oven to 350°F.

Crust

• Make crust. In a medium bowl, mix together 1 1/2 cups flour, 1 1/2 teaspoon sugar, 1 teaspoon salt, 1/2 cup oil, and 2 Tablespoons milk until well combined. Pat mixture evenly into the bottom and up the sides of a 9-inch pie pan. Do not roll out. (To smooth it out, use the back of a hot metal spoon and gently push down to smooth evenly.)

Filling

• Apple pie filling. In another medium bowl, stir 1/2 cup sugar, 2 Tablespoons flour, 1/2 teaspoon cinnamon, and 1/2 teaspoon nutmeg. Toss lightly with 4 cups sliced apples. Let sit 10 minutes for sugar mixture to melt onto the apples. Pour into the unbaked pie shell.

Crumb Topping

• Combine topping. In a small bowl, mix 1/2 cup flour, 1/2 cup salted butter, and 1/2 cup sugar with your fingers or a fork until crumbly. Sprinkle over pie. You’ll want to bake soon before the butter mixture softens too much.
• Bake pie. Place pie in brown paper bag and staple shut. Bake 1 1/2 hours. (If oven bakes hot, reduce to 325 degrees. No peeking.) Slit the bag open with sharp knife. Remove pie from oven and let cool completely so it thickens, about 4 hours.
• Serve. Serve the pie with vanilla ice cream and caramel on top, if desired.