Ingredients
1-1/4 cups all-purpose flour4-1/2 teaspoons sugarDash salt6 tablespoons cold butter, cubed1 large egg yolk, room temperature4 to 6 tablespoons ice waterFILLING:3 pounds medium sweet potatoes1-1/3 cups sugar2/3 cup butter, softened1/2 teaspoon pumpkin pie spiceDash salt4 large eggs, room temperature, lightly beaten2 teaspoons vanilla extractMERINGUE:1 cup sugar1/3 cup water1 tablespoon molassesDash salt5 large egg whites, room temperature3/4 teaspoon cream of tartar3/4 teaspoon pumpkin pie spice1/2 teaspoon ground ginger
Preparation
Pulse flour, sugar and salt in a food processor until blended. Add butter; pulse until butter is the size of peas. Combine egg yolk and 2 tablespoons ice water; slowly add to processor until dough holds together, adding remaining ice water, if needed, 1 tablespoon at a time. Shape dough into a disk; wrap and refrigerate 1 hour or overnight.
Preheat oven to 400°. Scrub sweet potatoes; pierce several times with a fork. Bake until tender, 45-50 minutes. Cool slightly; peel and mash to yield about 4 cups. Reduce oven setting to 350°.
On a lightly floured surface, roll dough to a 1/8-in.-thick circle; transfer to a 9-in. deep-dish pie plate. Trim to 1/2 in. beyond rim of plate; flute edge. Refrigerate 30 minutes.
For filling, beat sugar, butter, pie spice and salt until blended. Add eggs and vanilla; beat in cooled sweet potatoes until smooth. Add filling to chilled crust. Bake on bottom rack until a knife inserted in center comes out clean, 40-45 minutes. Keep warm.
Meanwhile, for meringue, combine sugar, water, molasses and salt in a small saucepan over medium-high heat;
using a pastry brush dipped in water, wash down the sides of the pan to eliminate sugar crystals. When mixture comes to a boil, stop brushing. Cook without stirring until a thermometer reads 240° (soft-ball stage).
As molasses mixture cooks, preheat broiler. Beat egg whites, cream of tartar and spices on medium speed until soft peaks form. While beating, gradually drizzle hot molasses mixture over egg whites; continue beating until stiff glossy peaks form. Spread meringue over warm pie; broil 4-6 in. from heat until slightly browned, 1-2 minutes. Cool on a wire rack.
