In dessert making, sweet potatoes are best known as the filling for a rich, dense, single-crust Southern pie. Yet they become surprisingly light when baked in a soufflé. Here, layers of paper-thin phyllo dough overlap to form a crisp pie shell, which stands tall as the filling cools and sinks (this is one soufflé that’s supposed to fall).
Recipe information
Yield
makes one 9-inch pie
Ingredients
For the Filling
For the Crust
Preparation
Step 1
Make the filling: Preheat oven to 400°F. On a parchment-lined rimmed baking sheet, bake potatoes until tender, 60 to 75 minutes. Let stand until cool enough to handle. Reduce heat to 375°F.
Step 2
Peel potatoes, and press through a ricer into a large bowl (you should have about 1 cup); let cool completely. Stir in ground ginger, vanilla, salt, egg yolks, and brown sugar.
Step 3
Meanwhile, in a medium saucepan, warm milk and fresh ginger over medium heat until just under a boil. Remove from heat; let stand 30 minutes. Pour through a fine sieve into a bowl and discard solids.
Step 4
In a saucepan over medium-high, melt butter. Whisk in flour; cook, whisking, 1 minute. Whisk in ginger-infused milk. Bring to a boil. Reduce heat to medium; cook 1 minute. Stir into potato mixture.
Step 5
Make the crust: Butter a 9-inch springform pan, and place on a parchment-lined rimmed baking sheet. Stir together 1/3 cup granulated sugar and 1/2 teaspoon cinnamon in a bowl. Brush 1 phyllo sheet with some melted butter. Sprinkle lightly with cinnamon-sugar mixture. Fold in half crosswise; brush with butter. Sprinkle lightly with cinnamon-sugar mixture, and fit into prepared pan, folded side in, allowing a 2 1/2 inch overhang. Repeat with each sheet, overlapping to cover bottom.
Step 6
With an electric mixer on high, whisk egg whites until foamy. Add cream of tartar; whisk until soft peaks form. With machine running, gradually add 1/4 cup granulated sugar; whisk until stiff glossy peaks form. Whisk one-third of egg whites into potato mixture. Using a wide flexible spatula, gently but thoroughly fold in remaining egg whites.
Step 7
Pour filling over phyllo; fold overhang over filling. Sprinkle with cinnamon-sugar mixture (if needed, combine 1 to 2 tablespoons more sugar with a pinch of cinnamon). Bake pie until puffed and just set in center, 45 to 50 minutes. Let pie stand until slightly cooled and center has fallen, about 20 minutes. Serve immediately.
