In a large bowl, combine the first six ingredients. In another bowl, combine the yogurt, egg and butter. Stir into dry ingredients just until moistened. Fold in blueberries.Drop by heaping tablespoonfuls 2 in. apart onto a greased baking sheet. Bake at 400° for 15-18 minutes or until lightly browned. Combine glaze ingredients; drizzle over warm scones.If using frozen blueberries, use without thawing to avoid discoloring the batter.