Add milk, eggs, and yolk, the 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. Cut out more rounds.
Transfer rounds to prepared cookie sheet, spacing evenly.
Brush with glaze. Bake until golden brown, about 25 minutes. Serve scones warm with strawberry preserves. In a large bowl, combine flour, sugar, baking powder, salt and cream of tartar. With a pastry blender, or two knives, cut in the butter until the mixture resembles coarse crumbs.