*We realize many people can't obtain maple syrup locally, so feel free to substitute supermarket maple-flavored syrup. The flavor won't be exactly the same, but you'll still have a delicious pie.
In a medium-size mixing bowl, whisk together the flour and salt. Using an electric mixer, a pastry blender or fork, or your fingers, cut the butter and shortening into the flour mixture until the fat and flour form a crumbly mixture. Add the lemon juice o
Flatten the ball of dough into a 1-inch thick circle, and transfer it to a well-floured work surface. Roll it into a 12-inch circle, using as few strokes of the rolling pin as possible; the less you fool around with the crust at this point, the more tende
Transfer the circle of dough to a 9-inch pie plate (a giant spatula works great here), and gently fit it to the pan's contours. Again, if you push and stretch the dough too much during this stage, it'll shrink when you put it in the oven. Crimp the edges
Line the crust with parchment or waxed paper and fill it partway with pie weights or dried beans. Or set a perforated pie pan onto the crust. Bake the crust in a preheated 425°F oven for 15 minutes, then transfer it to a cooling rack, remove the pie weigh
In a large bowl, beat the eggs till well-combined, then add the maple syrup in a slow stream, beating all the time. Stir in the melted butter, vanilla and salt, then the walnuts. Pour the filling into the prepared crust.
Bake the pie at 375°F for 40 to 45 minutes, until it's somewhat puffed, bubbling, and a knife inserted in the center comes out clean. The crust will be a deep, golden brown. Remove the pie from the oven, and let it cool at least 30 minutes before serving