Combine all-purpose flour and kosher salt in a food processor. Cut in cold unsalted butter until resembling coarse crumbs. Gradually add ice water until a dough forms. Shape into a disc, wrap in plastic, and chill for 1-2 hours.

Preheat oven to 375°F (190°C). Roll out chilled dough and transfer to a pie dish, crimping edges. Chill again for 30 minutes, line with parchment, fill with weights, and bake for 15 minutes. Remove weights and bake for another 5-10 minutes until lightly golden.

In a large bowl, whisk together apple butter, large eggs, dark brown sugar, and sifted flour until smooth. Stir in vanilla extract and sweetened condensed milk until creamy.

Pour filling into pre-baked crust, smoothing with a spatula. Bake at 325°F (160°C) for 40-45 minutes until edges are set but center jiggles slightly.

Remove from oven and cool on a wire rack for about 3 hours.

Whip heavy cream with powdered sugar, ground cinnamon, and vanilla extract until soft peaks form.

Spread cinnamon whipped cream over cooled pie and enjoy!