1.Preheat oven 180°C (160°C fan forced) Grease and flour a 12 x⅓ -cup capacity muffin pan (or lightly grease a silicone muffin tray).
2.Dissolve coffee in 1 tablespoon of boiling water. Finely grate rind from orange (use juice from orange for icing). Place muffin mix and grated orange rind in a large bowl, make a well in the centre, add egg and 1 cup cold water and stir with a wooden spoon until combined.
3.Transfer ¾ cup of the muffin batter to a separate bowl, add cold coffee mixture and mix to combine. Spoon the orange-flavoured batter evenly into prepared muffin pan, then divide the coffee-flavoured batter over each one. Lightly swirl coffee batter through the orange batter using a round-bladed knife to produce a rippled effect.
4.Bake in preheated oven 20-25 minutes or until muffins spring back when lightly touched in the centre. Stand muffins in pan for 5 minutes, then transfer to a wire rack to cool.
5.To make icing, sift icing sugar into a bowl, stir in butter and enough orange juice (about 2 teaspoons) to make a thick smooth icing. Spoon icing over muffins. Decorate with chocolate coated coffee beans if desired.