Butternut Squash Chess Pie

For The Crust
1 1/2 cup all-purpose flour
1 tablespoon granulated sugar
1/2 teaspoon salt
4 tablespoons cold butter, cut into small pieces
4 tablespoons frozen vegetable shortening
3 to 4 tablespoons ice water

For The Filling

1 medium butternut squash
vegetable oil (for roasting the squash)
1 1/4 cups granulated sugar
1/4 cup packed light brown sugar
2 tablespoons fine cornmeal
1/2 teaspoon salt
4 large eggs
6 tablespoons butter, melted and cooled
1/2 cup buttermilk
Finely grated zest and juice of 1 lemon
1 teaspoon pure vanilla extract

Make the crust:  Pulse the flour, granulated sugar, and salt in a food processor to combine.  Add the butter and pulse several times.  Add the shortening and pulse until the butter and shortening are incorporated, with pea-sized pieces remaining.  With the processor running, begin to drizzle in the water.  You may not need to add all the water.  Just as the dough begins to come together, stop adding water, and pulse until a ball forms in the bowl of the processor.  Remove the dough to a sheet of plastic wrap.  Shape into a flattened round about 6 inches in diameter.  Chill for at least one hour before rolling.

Unwrap the dough and place it on a lightly floured surface.  Roll the dough to a 12-inch round.  Transfer it to a 9-inch pie dish. Flute the edge by pinching the dough together between your fingers or by pressing down with the tines of a fork.  Using a fork, prick the dough around the sides and across the bottom.  Cover the pie dish with plastic wrap and chill for 30 minutes before baking.

Preheat the oven to 375˚F.

Remove the crust from the refrigerator.  To avoid shrinkage while baking, line the crust with foil and fill with pie weights, rice, or dried beans.  Bake in a preheated oven for 15 minutes with the weights, then remove the foil and the weights and continue baking for an additional 10 to 15 minutes or until golden brown.  Remove to a cooling rack and cool completely before filling.

Meanwhile, make the filling:  Cut the butternut squash in half and remove the seeds.  Rub the surface of each half with vegetable oil and place flesh side down onto a parchment or foil lined baking sheet.  Roast the squash for 30 to 40 minutes, or until easily pierced with a knife.  Let cool slightly, scoop out the flesh and transfer it to a mini food processor; puree until very smooth, about 1 minute.  (You will need 1 cup of squash puree.)

Whisk the granulated sugar, brown sugar, cornmeal and salt in a medium bowl.  Whisk the squash puree, eggs, melted butter, buttermilk, lemon zest and juice and the vanilla in a large bowl; add the sugar mixture and whisk.  Pour the filling into the cooled crust.  Bake until the filling is set in the middle, 50 to 55 minutes.  If the edges of the crust begin to brown too much, cover them with foil.  Transfer to a rack and let cool completely.