sweet potato buttermilk pie

INGREDIENTS

• 1 1/2 pounds sweet potatoes (about 2 medium potatoes), peeled and chopped into a 1/2-inch dice
• 4 tablespoons unsalted butter, melted
• 2 tablespoons fresh lemon juice (optional)
• 1/2 teaspoon freshly grated nutmeg
• 1/2 teaspoon ground cinnamon
• 1/2 teaspoon kosher salt
• 3 large eggs, separated
• 1/2 cup sugar
• 2 tablespoons all-purpoe flour
• 3/4 cup full- or lowfat buttermilk (or, you can
• )
• 1
• (a half recipe will yield a single crust), prebaked (instructions below)
• Whipped cream, for serving