How to Make It
Prepare the Crust: Pulse flour, granulated sugar, and salt in a food processor until combined, 2 to 3 times. Scatter butter and shortening over flour mixture; pulse until mixture resembles coarse sand, 4 to 5 times. Sprinkle ice water over top; pulse until mixture starts to clump, 4 to 5 times. Transfer mixture to a lightly floured work surface; knead until dough comes together, 4 or 5 times. Wrap one-third of dough with plastic wrap; wrap remaining dough with plastic wrap. Chill 1 hour
Prepare the Filling: Whisk together granulated sugar and flour in a large bowl. Stir in corn syrup, melted butter, brown sugar, bourbon, vanilla, and eggs until well combined
Preheat oven to 350°F. Lightly coat a 15- x 10-inch rimmed baking sheet with cooking spray. Unwrap larger dough portion, and roll into a 17- x 12-inch rectangle on a lightly floured surface. Fit dough into bottom and up sides of prepared baking sheet. Tuck edges under and crimp.
Unwrap smaller dough portion, and roll into a 1/4-inch-thick circle. Using 2-inch and 3-inch leaf-shaped cutters or other cutters, cut desired number of shapes from dough.
Sprinkle pecans and white chocolate chips evenly over bottom of piecrust. Pour filling over pecans and white chocolate chips. Arrange dough cutouts on top of filling.
Using a fork, stir together egg yolk and water in a small bowl. Brush egg mixture on edges of pie and on cutouts.
Bake in preheated oven until filling is almost set but still slightly jiggly in the center, 40 to 45 minutes. (Shield edges with aluminum foil after 30 minutes, if necessary, to prevent excessive browning.) Cool completely on a wire rack, about 1 hour.
Prepare the Caramel Sauce: Bring granulated sugar, butter, and salt to a boil in a large saucepan over medium, stirring often. Boil, stirring often, until mixture turns amber, 5 to 6 minutes. Stir in cream; return to a boil, stirring occasionally. Boil, stirring often, until sugar melts and mixture is smooth, about 3 minutes. (Sugar mixture may harden but will melt as it cooks.) Remove pan from heat; stir in vanilla. Serve warm or cool.