1 single pie crust
For the filling:
5 cups (about 2 lbs) apples, peeled and sliced (Granny Smith work well)
1 cup granulated sugar, divided
1/2 teaspoon ground cinnamon
1/4 teaspoon ground nutmeg
2 tablespoons all-purpose flour
1/4 teaspoon salt
3 large eggs
1 3/4 cups buttermilk
1/2 teaspoon vanilla extract
For the topping:
1/3 cup all-purpose flour
1/3 cup brown sugar
1/2 teaspoon cinnamon
3 tablespoons chilled butter, cut into small cubes
Preheat oven to 325°F.
Roll dough into a 14-inch circle and line a 9-inch deep dish pie pan. Fold under edges and use your fingers to flute them. Place in refrigerator until ready to fill.
Meanwhile, make the filling:
Spray a large nonstick skillet with cooking spray and place over medium heat. Add apples, 1/4 cup of the sugar, cinnamon, and nutmeg. Cook until apples are tender, stirring occasionally, about 10 minutes. Spoon apple mixture into prepared crust.
In a medium bowl, whisk together the remaining sugar, flour, salt, and eggs, followed by the buttermilk and vanilla. Pour over apple mixture.
Bake pie for 30 minutes. Meanwhile, make the topping:
In a small bowl, stir together the 1/3 cup flour, brown sugar, and cinnamon. Cut butter in with a pastry blender or two knives until mixture is crumbly but combined.
After 30 minutes, reduce oven temperature to 300°F. Sprinkle streusel topping over the top of the pie and continue baking until set, about 40 minutes. Let cool 1 hour before slicing and serving. Enjoy!