Sweet Potato Pie

Preparation

1. For crust:

   Step 1

   Mix flour, sugar, and salt in processor. Add butter and shortening; using on/off turns, cut in until mixture resembles coarse meal. Drizzle 3 tablespoons ice water over mixture. Process until moist clumps form, adding more ice water by teaspoonfuls if dry. Gather dough into ball; flatten into disk. Wrap in plastic; chill until firm, about 30 minutes.

   Step 2

   Roll out dough on floured surface to 14-inch round. Transfer to 9-inch-diameter glass pie dish. Fold overhang under. Crimp edges decoratively. (Crust can be made 2 days ahead. Cover; chill.)

2. For filling:

   Step 3

   Pierce potatoes with fork. Cook in microwave on high until tender, about 6 minutes per side. Cut open; cool completely. Scrape potato flesh into bowl; mash until smooth. Measure enough potato puree to equal 1 1/2 cups.

   Step 4

   Position rack in bottom third of oven; preheat to 400°F. Place puree in large bowl. Whisk in brown sugar and next 6 ingredients. Brush crust with beaten egg white. Transfer filling to crust.

   Step 5

   Bake pie until filling is puffed around edges and set in center, about 45 minutes. Transfer to rack; cool. (Can be made 1 day ahead. Cover; refrigerate.)