Make the crust:
Mix the flour, sugar and salt. Then, using a fork, cut the butter and shortening into the flour mixture until you have balls of fat no larger than peas.
Drizzle ice-cold water over the flour, 1 tbsp at a time, stirring with the fork, until the dough starts to come together. Once it holds together, turn it onto a lightly floured platform, shape into a disc, and wrap tightly in plastic wrap. Refrigerate for at least 30 minutes.
To roll the pie dough, remove it from the plastic wrap and roll into a disc large enough to fit over a 9-inch pie plate with some overhang. Transfer the dough to the pie plate and crimp the edges to make a decorative border. The easiest way to do this, if you're not used to it, is to take a fork and press all around the edge in a decorative pattern.
Now you need to blind bake the crust. What this means is baking the crust without the filling. But placing a crust by itself in the oven causes it to shrink, so take a piece of aluminum foil and smooth it over the crust, making sure you push it against the sides and bottom of the crust. Let a little bit of foil hang over the edge so the edge will not brown too fast.
Now fill the crust with uncooked rice or uncooked beans (these act as weights to keep your crust in place), making sure you fill all the way to the top. I have a box of rice that I use again and again to blind-bake crusts-- after I am done, I just store it until I need it the next time. Do not cook the rice or beans that you use to blind bake.
Place the pie pan, rice or beans and all, into a 400-degree preheated oven and bake for 20 minutes.
Remove from the oven and carefully lift off the foil and the weights. Now pierce the crust all over with a fork and return it to the oven for 5 more minutes until it is lightly golden-brown.
Make the filling:
Whisk all the filling ingredients together in a large bowl or in a food processor (the way I did it).
Pour the pie filling into a warm crust and bake in a preheated 375-degree oven for 45-50 minutes or until the filling is set but slightly quavery. Remove the pie to a rack and cool completely before serving.