Fresh Orange Muffins

Makes 12 oil or melted butter, for greasing(if using) 5 oranges 1 cup whole wheat flour 1 cup all-purpose flour 1 tbsp baking powder heaping 1/2 cup superfine sugar 2 large eggs 1 cup fresh orange juice 6 tbsp sunflower oil  Preheat the oven to 400 degrees. Grease a 12-cup muffin pan or line with 12 muffin pan liners. Finely grate the rind from 2 of the oranges and set aside. Using a serrated knife, remove the peel from all of the oranges, discarding the white peel. Cut the flesh into segments, reserving 6 segments. Cut the reserved segments in half and set aside. Coarsely chop the remaining orange segments. Sift together both types of flour and the baking powder into a large bowl, adding any bran left in the sifter. Stir in the sugar. Lightly beat the eggs in a large pitcher or bowl,then beat in the orange juice,oil,and reserved orange rind. Make a well in the center of the dry ingredients,pour in the beaten liquid ingredients,and add the chopped oranges. Stir gently untii just combined; do not overmix. Spoon the batter into the prepared muffin pan. Place the reserved halved orange segments on tops of the muffins. Bake in the preheated oven for about 20 min. until well risen,golden brown,and firm to the touch. Let the muffins cool in the pan for 5 min. then serve warm or transfer to a wire rack and let cool completely.