
Place the butter in a large microwave-safe mug. Microwave on high for 20 seconds or until the butter is melted. Stir through the sugars and vanilla essence.
Add the plain flour, baking powder and salt and stir until a soft dough comes together. Stir through the chocolate chips. Flatten down the dough down into the mug then top with extra chocolate chips, if desired.
Microwave for 1 minute (based on an 1100 watt microwave). Allow to cool for 1 minute before eating. Enjoy!