Blueberry Buttermilk Scones (a la Martha)

These scones are absolutely delicious, and were a tremendous hit when I baked them for my parents' 40th anniversary brunch. According to Martha, the secret to making delicate scones is handling the dough as little as possible. Another tip: If you don't have buttermilk, you can substitute 1/2 cup plain yogurt whisked with 2 tablespoons milk. One final note: make sure to drizzle the wet mixture into the dry mixture slowly, and give the batter a good mix in the middle using a fork. Otherwise, the better ends up too wet and is very difficult to handle.

Ingredients
Makes 1 dozen

• 1 1/2 cups all-purpose flour
• 1/2 cup cake flour (not self-rising)
• 3 tablespoons granulated sugar
  
• 2 1/2 teaspoons baking powder
• 3/4 teaspoon salt
• 4 ounces (1 stick) cold unsalted butter, cut into small pieces
• 1 cup (1/2 pint) blueberries (raisins work as well)
  
• 1/2 cup low-fat buttermilk
• 1 large egg, plus 1 large egg lightly beaten for egg wash
• 1/2 teaspoon pure vanilla extract
• Fine sanding sugar, for sprinkling

Directions

1. Preheat oven to 375 degrees. Line a baking sheet with parchment paper.
2. Whisk together flours, granulated sugar, baking powder, and salt in a large bowl. Cut in butter with a pastry cutter, or rub in with your fingers, until mixture has the texture of coarse meal. Stir in blueberries.
3. Whisk together buttermilk, 1 egg, and the vanilla. Drizzle over flour mixture, and stir lightly with a fork until dough comes together but a small amount of flour remains in bowl.
4. Turn out dough onto a work surface, and gently knead dough once or twice just to incorporate flour. Pat dough into a 1-inch-thick round. Cut into 12 wedges. Transfer to prepared baking sheet. Brush with egg wash, and sprinkle with sanding sugar. Bake until golden brown and cooked through, about 22 minutes. Transfer scones to wire racks to cool. Scones are best served immediately but can be frozen for up to 1 month. Thaw, and reheat in a 350-degree oven for 10 minutes.