Preheat Oven to 180 degree C. Oil a muffin tray or line it with cupcake cases. Set aside.
Sift flour, cocoa, baking soda and baking powder. Set aside.
Take butter, sugar and vanilla in a bowl and use a electric beater to cream well.
Add in egg and cream till fluffy.
Now add in half flour mix and fold gently. Add in milk and mix gently.
Add in remaining flour and fold gently. Add in orange zest and fold gently.
Use a icecream scoop to fill the cupcake moulds. Bake for 20 to 25 mins. Remove it and let it cool for 10 mins,
Once it is cooled, remove it from cases and let it cool down completely.
While the cupcake is cooling make frosting.
Take chocolate, butter, 4 tblspn of orange juice in a sauce pan.. Melt it till molten.
Add in icing sugar and mix well
Pour this into a bowl and chill it for 30 mins.
Now remove it from fridge and use a beater to beat till creamy.
If it is too stiff, add some orange juice and beat.
Once it is creamy. frost your cupcakes and enjoy..