In a food processor, pulse together all-purpose flour, granulated sugar, and salt until mixed.

In a separate bowl, whisk the egg, white vinegar, and a tablespoon of cold water.

Add cold butter cubes to the flour mixture, processing until crumbly, then mix in the egg mixture until the dough forms.

Shape it into a disk, wrap it in plastic, and chill for 30 minutes.

Roll out the chilled dough on a floured surface until about 1/8-inch thick.

Fit the rolled dough into a 9-inch pie plate, trimming any excess.

Chill the crust again for 15 minutes, preheat the oven to 375°F.

Line the crust with parchment paper and fill with pie weights. Bake for 15 minutes, then remove the weights and let it cool.

In a mixing bowl, whisk together eggs, pure canned pumpkin, sour cream, bourbon, vanilla extract, and warm spices until smooth.

Heat pure maple syrup over low heat, stir in heavy cream, then fold into the pumpkin mixture.

Carefully pour the filling into the pre-baked crust. Bake at 350°F for 55-60 minutes, until set with a slight jiggle.

Allow the pie to cool on a wire rack for at least 2 hours, then refrigerate overnight.

Before serving, sprinkle granulated sugar on top and caramelize using a kitchen torch or broiler.