Instructions

1. Prepare the Sweet Potatoes

Preheat the oven to 400°F (200°C). Place sweet potatoes on a baking sheet and bake for 1 hour, or until tender. Let cool for 10 minutes, then peel off the skins.

Measure out 1 1/4 cups of mashed sweet potatoes. For a smoother texture, use a hand mixer to blend until creamy. This step can be done up to 2 days in advance.

2. Prepare the Pie Crust

Reduce oven temperature to 450°F (230°C). Unroll the pie crust into a 9-inch pie plate, shaping and crimping the edges. Prick the bottom and sides with a fork and bake for 9–11 minutes. Remove and cool, then reduce oven temperature to 375°F (190°C).

3. Make the Filling

In a medium bowl, combine mashed sweet potatoes, melted butter, lemon juice, nutmeg, cinnamon, and salt. Stir until smooth.

In a separate large bowl, whisk egg yolks until thick and pale. Add granulated sugar and brown sugar, whisking for about 1 minute. Stir in the sweet potato mixture until well blended.

Gradually whisk in the flour, one teaspoon at a time, then mix in the buttermilk until smooth.

4. Add Egg Whites

Using an electric mixer, beat egg whites until soft peaks form. Gently fold the egg whites into the sweet potato batter using a spatula.

5. Bake the Pie

Pour the batter into the cooled pie crust. Bake at 375°F (190°C) for 35–40 minutes, or until the center is set and a knife inserted in the middle comes out clean.

Allow to cool completely before slicing. Serve plain or with a dollop of whipped cream.