Sour Cream Pumpkin Pie

• Roll out pastry dough on a lightly floured surface with a lightly floured rolling pin into a 13-inch round and fit into a 9-inch glass or metal pie plate. Trim excess dough, leaving a 1/2-inch overhang, then fold overhang under pastry and press against rim of pie plate to reinforce edge. Decoratively crimp edge and chill shell until firm, about 30 minutes.
• While shell chills, put oven rack in middle position and preheat oven to 375°F.
• Lightly prick bottom and side of chilled pie shell all over with a fork. Line shell with foil and fill with pie weights. Bake until pastry is pale golden along rim and set underneath weights, about 20 minutes. Carefully remove foil and weights and bake shell until bottom and side of pastry are pale golden, about 10 minutes more. Cool completely in pie plate on a rack, about 20 minutes. Leave oven on.

Make filling:

• Heat 1 cup sour cream in a double boiler or a large metal bowl set over a large wide pot of boiling water until warm, stirring occasionally.
• Whisk together pumpkin, yolks, brown sugar, cinnamon, nutmeg, ginger, salt, and remaining 1/2 cup sour cream in another bowl until combined and whisk into hot sour cream. Cook over simmering water, stirring constantly with a wooden spoon, until thickened and registers 170°F on thermometer, about 6 minutes. Remove from heat and cool pumpkin mixture in bowl set in a larger bowl of ice water, stirring occasionally, about 15 minutes.
• Beat egg whites in another bowl with an electric mixer until they just hold stiff peaks. Fold whites into pumpkin mixture gently but thoroughly.
• Pour filling into cooled shell, smoothing top, and bake until filling is set and puffed around edge, 40 to 50 minutes. Cool pie to room temperature on a rack, about 2 hours.