Robert Stehling's Buttermilk Pie - Andrew Zimmern

Ingredients

• 6 tablespoons unsalted butter, room temperature
• 1 cup granulated sugar
• 2 eggs, separated
• 3 tablespoons all-purpose flour
• 1 tablespoon fresh lemon juice
• 1/2 teaspoon freshly grated nutmeg
• 1/4 teaspoon salt
• 1 cup buttermilk, room temperature
• 1 baked 9-inch deep-dish pie shell