Prep Time: 20 minutes
Cook Time: 40 minutes
Total Time: 1 hour
- 1 8-inch pie crust
- 1 1/2 lb. sweet potatoes; peeled and cut into 1/2" cubes
- 4 Tbsp. unsalted butter; melted
- 2 Tbsp. fresh lemon juice
- 1/2 tsp. grated nutmeg
- 1/2 tsp. ground ginger
- 1/2 tsp. kosher salt
- 3 lg. eggs; separated
- 1/2 cup sugar
- 6 tsp. all-purpose flour
- 1/4 cup whole buttermilk
1. Heat oven to 375 degrees.
2. Poke crust with a fork. (This is called docking and prevents large bubbles from forming).
3. Line the crust parchment paper, fill with dried beans (this also minimizes bubbles) and bake until lightly puffed and lightly browned. (This is called blind baking.)
4. Separate the eggs, cover, and allow whites to warm for about 1 hour. (Warm egg whites can incorporate more air than cold whites.) The yolks can be refrigerated until ready to use.
5. Steam sweet potatoes until tender, about 20 minutes. Allow to cool.
6. In a large mixing bowl, mash potatoes with a fork or potato masher. Add butter, lemon juice, nutmeg, cinnamon, and salt and mix thoroughly.
7. Beat the egg yolks lightly, add the sugar, and continue beating until the mixture is is a creamy yellow color.
8. Stir the yolk mixture into the sweet potatoes mix thoroughly. Add the flour, about a teaspoon at a time, mixing well after each addition. Stir in buttermilk.
9. Beat egg whites until they form soft peaks. Fold a third of the whites into the sweet potatoes mixing well, but gently. Fold remaining whites into the potatoes.
10. Pour filling into pie crust and cook in the center of the oven until the center of the pie is set - about 40 minutes.
11. Cool pie completely on a rack and serve either at room temperature or cold.