1. Preheat the oven to 180˚C/160˚C fan/gas mark 4. Line the bottom of a 20cm tin with non-stick parchment paper and grease the sides.
2. In a large bowl, beat together the butter and brown sugar until light and fluffy. Add the vanilla.
3. Beat in the egg until combined.
4. Add in the flour, baking powder and chocolate chips. Mix until just combined.
5. Transfer the mixture into the prepared tin and press it in, making an even layer.
6. Bake for 15-20 minutes or until golden brown. Leave to cool completely.
7. To make the icing, combine the cream cheese, icing sugar and cocoa in a bowl and beat together until smooth. Spoon into a piping bag with a star nozzle.
8. Pipe swirls of the icing around the outer edges of the cooled cookies. Decorate with sprinkles and serve.

Note: Chopped chocolate can be used as an alternative to chocolate chips, if you wish.

Per Serving: 478kcals, 27.1g fat (17.2g saturated), 53.9g carbs (32.5g sugars), 7g protein, 2.2g fibre, 0.186g sodium