To make the crust, place the flour, salt and sugar in a bowl. Cut the butter and shortening into small cubes and add to the flour. Using a pastry cutter or two forks, cut in the fat into the flour until you have smallish pieces of fat dispersed through the flour, no larger than the size of peas.
Drizzle in the icy water, a little at a time, until the dough comes together in a ball.
Clump the dough together and place it in plastic cling wrap, shaping into a disc as you wrap it.
Refrigerate for at least 30 minutes.
Using some flour, roll the pie crust into a round large enough to fit into your pie plate with a slight overhang. Place in the pie plate and tuck in the excess under the rim.
Crimp or flute the corners to make a decorative edge. You can also just press around the edges with the tines of a fork to get a nice-looking crust.
You will need to blind-bake the crust-- meaning you need to par-bake it before adding the filling. To do this, smooth a piece of aluminum foil (shiny side up) over the crust, making sure you cover the crust entirely. Now fill the pie crust all the way to the top with dry rice or beans (these are used as pie weights-- they prevent the pie crust from shrinking which it would do if you didn't add the pie weights. Keep the dry rice or beans that you use for all your future blind-baking needs-- don't throw it away).
Place the pie crust in a 400-degree (Fahrenheit) oven for 20 minutes. Then remove from the oven, carefully pour out the rice or beans, and remove the aluminum foil. Poke some holes into the bottom of the crust with a fork, and put it back in the oven for another five minutes. Remove the crust from the oven and set aside.
To make the filling, combine all the ingredients in a food processor and pulse until you have a very smooth mixture.If you don't have a food processor, combine the ingredients in a large bowl and mix with a whisk until everything's well-blended.
Pour the filling into the warm crust.
Bake in a 375-degree oven for 55 minutes or until the filling is set and only slightly jiggly in the center.
Cool thoroughly before serving.