Warm apple buttermilk custard pie - Untested

 https://www.myrecipes.com/recipe/warm-apple-buttermilk-custard-pie-0

Streusel:

⅓ cup all purpose flour

⅓ cup packed brown sugar

½ teaspoon ground cinnamon

2 ½ tablespoons chilled butter, cut into small pieces

Filling:

5 cups sliced peeled Granny Smith apple (about 2 pounds)

1 cup granulated sugar, divided

½ teaspoon ground cinnamon

2 tablespoons all-purpose flour

¼ teaspoon salt

3 large eggs

1 ¾ cups fat-free buttermilk

1 teaspoon vanilla extract

1. Preheat oven to 325º.
2. To prepare crust, roll dough into a 14-inch circle; fit into a 9-inch deepdish pie plate. Fold edges under; flute. Place pie plate in refrigerator until ready to use.
3. To prepare streusel, lightly spoon 1/3 cup flour into a dry measuring cup; level with a knife. Combine 1/3 cup flour, brown sugar, and 1/2 teaspoon cinnamon in a medium bowl; cut in butter with a pastry blender or 2 knives until the mixture resembles coarse meal. Place streusel in refrigerator.
4. To prepare the filling, heat a large nonstrick skillet coated with cookig spray over medium heat. Add sliced apple, 1/4 cup granulated sugar, and 1/2 teaspoon cinnamon; cook 10 minutes or until the apple is tender, sitrring mixture occasionally. Spoon the apple mixture into prepared crust.
5. Combine remaining 3/4 cup granulated sugar, 2 tablespoons flour, salt, and eggs, stirring with a whisk. Stir in buttermilk and vanilla. Pour over apple mixture. Bake at 325º for 30 minutes. Reduce oven temperature to 300º (do not remove pie from oven); sprinkle streusel over pie. Bake at 300º for 40 minutes or until set. Let stand 1 hour before serving.