In small bowl blend the sour cream and baking soda and set aside. Preheat oven to 350 degrees. Lightly grease a baking sheet. In large bowl mix the flour, sugar, baking powder and cream of tartar. Cut in the butter. Stir the sour cream mixture and egg into the flour mixture until just moistened. Fold in the cranberries/cherries. Turn dough onto a lightly floured surface and knead briefly. Roll dough into a 3/4 inch thick round, cut into 12 wedges and place 2" apart on baking sheet. Bake 12 - 15 minutes in oven until golden brown on the bottom.
To drizzle with icing, add a little water to powdered sugar until drizzling consistency. Add in grated orange peel and drizzle over scones.