In a food processor, pulse together all-purpose flour, granulated sugar, and salt until well mixed. In a separate bowl, whisk together the egg, white vinegar, and cold water. Cut in the cubed unsalted butter, then gradually add the liquid mixture until coarse crumbs form. Transfer the dough to a disk shape, wrap in plastic, and refrigerate for 30 minutes to chill.

Preheat your oven to 375°F (190°C). On a floured surface, roll the chilled dough into a 12-inch circle, then carefully place it in a pie plate. Prick the bottom with a fork to prevent bubbling, then bake for 15 minutes until lightly golden. Remove from the oven and brush the crust with egg white to seal, allowing it to cool slightly.

In a large mixing bowl, whisk together eggs, pure canned pumpkin, and sour cream until smooth. Gradually add in the smoky bourbon and vanilla extract, followed by the warm pure maple syrup, heavy cream, and your choice of spices until well combined. Ensure the mixture is creamy and free of lumps.

Pour the prepared pumpkin mixture into the pre-baked crust, spreading it evenly. Place the pie in the oven and bake at 350°F (175°C) for 55-60 minutes, or until the filling is set but slightly jiggles in the center when gently shaken. Remove from the oven and let it cool completely before refrigerating overnight to develop flavors.

Just before serving, sprinkle an even layer of granulated sugar over the entire surface. Using a kitchen torch, caramelize the sugar until it bubbles and turns golden brown. Be attentive to prevent burning.