Greek Yogurt Blueberry Scones

• 1 and 1/2 cups all-purpose flour
• 1 cup whole wheat flour
• 1/2 teaspoon salt
• 1 tablespoon baking powder
• 1/2 teaspoon baking soda
• 1/4 cup granulated sugar
• 1 teaspoon lemon zest
• 1 stick (4 ounces) unsalted butter, VERY cold and cut into tiny pieces
• 1 large egg, beaten
• 1/2 cup non-fat Greek yogurt
• 3 tablespoons whole milk
• 2 teaspoons pure vanilla extract
• 1 cup blueberries, fresh or frozen (If using frozen, do not thaw first)

For the egg wash:

• 1 large egg, beaten
• 1 teaspoon milk or water
• 2 tablespoons Sugar, for sprinkling

For the (optional) lemon glaze:

• 2 tablespoons fresh lemon juice
• 3/4 cup confectioners sugar