Preheat oven to 375 degrees F. Butter and flour heavy large cookie sheet. Mix first 5 ingredients in large bowl. Add butter and cut in until mixture resembles fine meal. Add milk, eggs and yolk, then raisins, and mix until thoroughly incorporated. Turn dough out onto lightly floured surface. Press dough into 1-inch-thick round. Cut out rounds using floured 3-inch round cookie cutter. Gather scraps and re-form into 1-inch-thick round. Cut out more rounds.
Transfer rounds to prepared baking sheet, spacing evenly. Brush with glaze. Refrigerate 15 minutes. Bake until golden brown, about 25 minutes. Serve scones warm with berry preserves.
Makes about 10. From Bon Apetite magazine.