Preheat the oven to 425° F.

Line a baking sheet with parchment paper.

In a food processor with a steel blade, combine the flour, salt, and sugar.  Pulse briefly to combine.

Add the cold cubed butter and process for about 5 seconds until a coarse meal develops.  Add the vodka and cold water and process for another 5 seconds or so until the dough ball forms.

Transfer the dough to a lightly floured surface and knead a few times, just until the dough comes together into a ball.  Pat the dough into a disk and cover with plastic wrap and refrigerate for 30 minutes.

Prepare the pears by slicing the pears and removing the core with a teaspoon or melon baller and set them aside.

Prepare the pecan crumble by combining melted butter, flour, chopped walnuts, brown sugar, cinnamon, and salt in a medium-sized bowl. Stir with a fork until ingredients are combined and wet crumbles form. Set aside.

Remove the dough from the refrigerator and let it come to room temperature for 5 - 10 minutes.  Sprinkle flour on the parchment paper and place the disk onto the floured parchment paper.

Using a rolling pin, roll the dough into a 12" circle about 1/8" thick, adding more flour as necessary to prevent the dough from sticking.   Transfer the rolled dough and parchment paper to a baking sheet.

Arrange the pears decoratively on top of the pie crust, fanning them out to lie fairly flat. Leave a 1½-inch border of crust around the perimeter.

With your hand, sprinkle crumble mixture into crevices between pears and into any open areas along the perimeter of the pears. Try to keep most of the sliced pears exposed for a pretty presentation.

Fold the edges of the dough up and over the filling, pleating edges when needed. The center should remain open.

Brush the edges of the dough with egg wash and sprinkle the edges and pears with turbinado sugar.

Bake until crust is golden and fruit is tender 40 to 45 minutes. Transfer to a cooling rack and let cool completely before slicing.