Apple and Oat Scones with Cinnamon and Nutmeg

INGREDIENTS

• 1 2/3 cups all-purpose flour, plus more for rolling
• 1 1/3 cups old-fashioned rolled oats, plus more for topping
• 1/4 cup plus 2 tablespoons light-brown sugar
• 1/2 teaspoon ground cinnamon
• 1/2 teaspoon freshly grated nutmeg
• 2 teaspoons baking powder
• 3/4 teaspoon baking soda
• 1/2 teaspoon salt
• 1 1/2 sticks cold unsalted butter, cut into pieces
• 1 1/2 cups diced Granny Smith apple (2 apples cut into generous 1/4-inch cubes)
• 2/3 cup cold buttermilk, plus more for brushing
• Raw turbinado sugar, for sprinkling