Prepare flaky pie crust in advance. Cut firmly chilled butter and shortening into small pieces. Combine the flour, sugar, and salt in the bowl of a food processor. Pulse for 10 seconds. Add chilled shortening and butter and pulse for about 20 seconds longer, or until the pieces of mixture are about the size of very small peas. Add chilled water (or water and vinegar) and mix for about 10 seconds. Do not overmix or the dough will be tough.

Transfer to a floured cutting board and knead lightly until the mixture forms a dough. If the mixture is already together, immediately form the dough into a round disk about 5 inches in diameter and 1/2-inch thick. Cover with plastic wrap and refrigerate for at least 30 minutes.

Roll out the dough on a floured surface to a diameter of about 12 inches. Transfer the dough circle into 9-inch glass pie plate and crimp edges. Place in refrigerator for 20 minutes. While crust is resting, preheat the oven to 350 degrees F.

Toast pecans lightly on cookie sheet for 3 to 5 minutes. Also, cut a parchment paper circle the size of the bottom of the pie plate.

Prick the bottom of chilled crust with fork. Just before baking crust, set parchment paper circle on chilled dough and cover with a layer of dry beans or rice. Bake crust for 10 minutes, until the top edge just starts to brown. Remove beans/rice and paper and return crust to oven for about 5 minutes to lightly brown the crust bottom. If the crust edge is browning too quickly, cover the edge with foil or turn down the temperature of the oven to 325 degrees F. Remove crust from oven and cool.

Just before baking, make the Bourbon Pecan Pie filling: In a saucepan melt butter, and add remaining filling ingredients, except pecans. Over a low flame, stir filling until the mixture reaches about 100 degrees F on a candy thermometer.

Pour heated filling into prebaked crust and arrange the pecans decoratively on top. Bake until the filling has started to rise and a knife inserted into the center comes out sticky but hot, about 30 to 40 minutes. The pie will not be completely set in the center at this point but it will continue to cook a bit when out of oven. This method yields a rich, creamy texture. Cool for at least 1 hour and serve with sweetened whipped cream.