From Susan Purdy's cookbook As Easy As Pie. I add a little lemon juice to the crust with the ice water to ensure flakiness. Also make sure the fat you use for the crust is very cold.

Makes one 9-inch double-crust pie

Crust:
2 cups all-purpose flour
3/4 teaspoon salt
1/2 cup unsalted butter, chilled
3 tablespoons shortening or lard, chilled
1 tablespoon fresh lemon juice or unflavored vinegar
5 to 6 tablespoons ice water

Filling:
6 or 7 medium, fairly ripe pears (such as Anjou or Bartlett)
2 to 3 tablespoons fresh lemon juice
1/4 cup granulated sugar, plus extra for garnish
1/4 cup packed brown sugar
1/4 teaspoon ground cardamom
1/4 teaspoon ground nutmeg
1/4 teaspoon ground cinnamon
2 1/2 tablespoons quick-cooking tapioca or cornstarch
2 tablespoons unsalted butter, diced
1 to 2 teaspoons milk or cream

To make the Crust: In a large bowl, toss together the flour and salt. Have the ice water ready. Cut the butter and shortening into 1/2-inch cubes and use your fingers or a pastry blender to cut the fat into the flour. Continue blending until there are pieces the size of peas and corn. Drizzle in the lemon juice, tossing the ingredients together, then begin drizzling in the water. Toss thoroughly, but don't squash the mixture, until it begins to hold together. Set it aside for 5 minutes for the liquid to soak in, or form the dough into a disk on waxed paper, wrap well, and refrigerate for up to 1 day.

Preheat the oven to 425 degrees F. Roll out two-thrids of the dough between pieces of waxed paper until it is about 11 inches in diameter. Peel off the top sheet of paper, invert the dough over a 9-inch pie plate, and peel off the bottom sheet of paper. Ease the dough into the pan without stretching it, so that it fits into the corners. Use a paring knife to trim the edge to 3/4 inch beyond the pan edge. Refrigerate the crust. Roll out the remaining dough and scraps from the bottom crust, as above, until it is about 10 inches in diameter. Refrigerate the crust between the sheets of waxed paper.

To make the Filling: Peel, core, and slice the pears 1/4 to 1/2 inch thick and toss them in a large bowl with the lemon juice as you work. Add the 2 sugars, spices, and tapioca and toss well. Pour the filling into the refrigerated pie crust and scatter the diced butter on top. Peel off 1 sheet of paper from the top crust, invert it over the filling, and peel off the other sheet of paper. Fold the lip of the bottom crust together with the top crust to form a "wall" of crust at the edge. Crimp or pleat this edge as desired. Cut 3 or 4 slits in the top crust. You can refrigerate it at this point for several hours or bake right away. Before baking, brush the top crust lightly with milk or cream and scatter lightly with granulated sugar.

Bake the pie on the bottom rack of the oven for 12 minutes. Lower the temperature to 350 degrees, move the pie to the middle rack, and bake for 30 to 35 minutes longer, until the pastry is golden brown. You might also insert a knife into one of the slits to make sure the pears are tender. Mask the edges of the pastry with aluminum foil if they begin to get too dark before the filling is done. Remove the pie to a cooling rack and cool for at least 3 hours before slicing. When it is cool, wrap it well and store at room temperature.