goop | Sweet Potato Pie

Ingredients

• 1 cup packed light brown sugar
• 2 tablespoons all-purpose flour
• ½ teaspoon ground cinnamon
• ¼ teaspoon grated nutmeg
• ¼ teaspoon salt
• ½ cup milk
• ½ cup sour cream
• 3 large eggs
• 1 large egg yolk
• 1 teaspoon pure vanilla extract
• 2 cups puréed cooked sweet potatoes (about 1 to 4 pounds)
• 3 tablespoons unsalted butter