Preheat oven at 375. Prepare a baking sheet with cooking spray. To prepare batter, combine flour, brown sugar, baking powder, baking soda, cinnamon, and salt in a mixing bowl. Using a pastry blender, cut in margarine till pieces are the size of small peas. In another mixing bowl, combine egg white, milk, peel. and blueberries. Mix dry ingredients with wet ingredients just until moistened. Drop dough from rounded tablespoon 5 cm apart on prepared baking sheet. Bake for 10 to dozen minutes or until edges are set and lightly browned. Meanwhile, to prepare frosting, combine powdered sugar, 1 tablespoon margarine, peel and enough water to make of spreading consistency. ----