For the Dough

1. Process flour, sugar, and salt in food processor until combined, about 5 seconds. Scatter shortening over top and process until mixture resembles coarse cornmeal, about 10 seconds. Scatter butter over top and pulse until mixture resembles coarse crumbs, about 10 pulses.
2. Transfer mixture to bowl. Sprinkle ice water over mixture. Stir and press dough with spatula until dough sticks together. If dough does not come together, stir in up to 1 tablespoon ice water, 1 teaspoon at a time, until it does.
3. Transfer dough to sheet of plastic wrap and form into 4-inch disk. Wrap tightly in plastic and refrigerate for at least 1 hour or up to 2 days. Let chilled dough sit on counter to soften slightly, about 10 minutes, before rolling. (Wrapped dough can be frozen for up to 1 month. If frozen, let dough thaw completely on counter before rolling.)

Make the Pie

1. Roll dough into 12-inch circle on floured counter. Loosely roll dough around rolling pin and gently unroll it onto 9-inch pie plate, letting excess dough hang over edge. Ease dough into plate by gently lifting edge of dough with your hand while pressing into plate bottom with your other hand.
2. Trim overhang to 1/2 inch beyond lip of plate. Tuck overhang under itself; folded edge should be flush with edge of plate. Crimp dough evenly around edge of plate. Wrap dough-lined plate loosely in plastic wrap and refrigerate until firm, about 30 minutes. Adjust oven rack to middle position and heat oven to 350 degrees.
3. Line chilled pie shell with double layer of aluminum foil, covering edges to prevent burning, and fill with pie weights. Bake on foil-lined rimmed baking sheet until edges are set and just beginning to turn golden, 25 to 30 minutes, rotating sheet halfway through baking. Remove foil and weights, rotate sheet, and continue to bake crust until golden brown and crisp, 10 to 15 minutes longer. Transfer sheet to wire rack and let cool completely, about 45 minutes. Reduce oven temperature to 325 degrees.

For the Filling

1. Bring water, sugar, cornstarch, and salt to simmer in large saucepan, whisking constantly. When mixture starts to turn translucent, whisk in egg yolks, two at a time. Whisk in lemon zest and juice and butter. Return mixture to brief simmer, then remove from heat. Spray piece of parchment paper with vegetable oil spray and press directly against surface of filling to keep warm and prevent skin from forming.

For the Meringue

1. Bring water and cornstarch to simmer in small saucepan and cook, whisking occasionally, until thickened and translucent, 1 to 2 minutes. Remove from heat and let cool slightly.
2. Using stand mixer fitted with whisk attachment, whip egg whites, vanilla, and cream of tartar on medium-low speed until foamy, about 1 minute. Increase speed to medium-high and beat in sugar, 1 tablespoon at a time, until incorporated and mixture forms soft, billowy mounds. Add cornstarch mixture, 1 tablespoon at a time, and continue to beat to glossy, stiff peaks, 2 to 3 minutes.
3. Meanwhile, remove parchment from filling and return to very low heat during last minute or so of beating meringue (to ensure filling is hot).
4. With pie still on sheet, pour warm filling into cooled crust. Using rubber spatula, immediately dollop meringue evenly around edge of crust, spreading meringue so it touches crust (this will prevent the meringue from shrinking), then fill in center with remaining meringue. Using back of spoon, create attractive swirls and peaks in meringue. Bake until meringue is light golden brown, about 20 minutes. Let pie cool on wire rack until filling has set, about 2 hours. Serve.

Topping Lemon Meringue Pie

1. Using rubber spatula, immediately dollop meringue evenly around edge of crust, attaching meringue to pie crust to prevent shrinking. Then fill in center of pie.
2. Using back of spoon, create attractive swirls and peaks in meringue.