Tart Cherry-&-Vanilla Scones

3/4 cup dried tart cherries
1/4 cup boiling water
1 3/4 cups all-purpose flour
1/3 cup sugar
1/4 cup yellow cornmeal
2 teaspoons baking powder
1/4 teaspoon salt
2 tablespoons chilled stick margarine -- cut in small pieces
2 tablespoons vegetable shortening
1/3 cup plain nonfat yogurt
1/4 cup evaporated skimmed milk
1 teaspoon vanilla extract
1/4 teaspoon butter extract
Vegetable cooking spray
1 egg white -- lightly beaten
2 teaspoons sugar

Combine cherries and boiling water in a bowl; cover and let stand 10 minutes or until softened. Drain and set aside. Combine flour, 1/3 cup sugar, cornmeal, baking powder, and salt in a large bowl; cut in the margarine and shortening with a pastry blender or 2 knives until mixture resembles coarse meal. Combine cherries, yogurt, milk, and extracts, and add to dry ingredients, stirring just until dry ingredients are moistened (dough will be sticky). Pat the dough with floured hands into an 8-inch round cake pan coated with cooking spray.
Brush egg white over surface of dough, and sprinkle with 2 teaspoons sugar. Bake at 425 degrees for 20 minutes or until a wooden pick inserted in center comes out clean.