Combine dry ingredients in a medium mixing bowl. Work butter or margarine into dry ingredients, using a pastry blender or fork, until it is the size of small peas.
Combine milk, yogurt, egg, and vanilla in a small mixing bowl. Add dry ingredients, mixing just until the dry ingredients are moist. Stir in remaining ingredients.
Spoon about 1/2 cup of batter for each scone onto cookie sheet. Bake for 30 minutes or until golden brown.