Preheat oven to 180 degrees C. Line a muffin tin with 12 paper baking cups.
Combine flour sugar, baking powder, bicarb soda and salt. In another bowl mix butter, eggs, courgette and vanilla. Mix in the flour mixture and stir until well combined. Fold in the chocolate chips.
Spoon into the lined muffin cups. Bake in the preheated oven until a knife inserted in the centre comes out clean, about 30 minutes. Allow to cool on a wire rack before icing.
Beat together cream cheese, butter and vanilla until well mixed. Slowly beat in the icing sugar until the desired sweetness is reached. Pipe onto cooled cupcakes.
I'm not only cheeky, I'm cheap too. I don't have a piping bag, so I just cut the tip off the corner of plastic sandwich bag, spoon in the icing then pipe it on that way.
Also, I added a half a mashed banana to the courgette, because I didn't want to waste it, this is not necessary.
These look nice when sprinkled with chocolate hail or crushed up flake(TM). I just used cocoa powder and sprinkled it on with a fork.