In a large bowl, beat the butter, brown sugar, sugar blend and orange zest. Beat in the egg, egg white and 2 tablespoons orange juice. Combine the flour, baking powder, baking soda, salt and ginger; gradually add to the butter mixture alternately with buttermilk, beating well after each addition. , Coat 9 muffin cups with cooking spray or use paper liners; fill three-fourths full with batter. Bake at 350° until a toothpick inserted in the center comes out clean, 18-20 minutes. Cool for 5 minutes before removing from pan to a wire rack to cool completely., In a small bowl, combine confectioners' sugar and remaining 2 1/2 teaspoons orange juice. Frost cupcakes.