Heat oven to 450°F. Lightly grease cookie sheet. In a large bowl, combine first seven ingredients; mix well. Cut in margarine until crumbly. Stir in currants and orange peel. Add buttermilk, just until moistened. Turn onto a lightly floured surface; knead gently six to eight times. Roll dough to a 1/2" thickness. Cut with a floured biscuit cutter. Gather dough scraps together (do not knead); re-roll and repeat. Place on a prepared cookie sheet. Brush tops with melted margarine and sprinkle with remaining oats. Bake 10-12 minutes or until light golden brown. For icing, mix powdered sugar and buttermilk. Drizzle icing on each biscuit in the shape of a cross.
