In a microwaveable mug, place all the flour and cocoa powder. Use the spoon to grind all of the cocoa and flour against the side of the mug so there are no lumps.
Add the egg and beat a little on top of the dry ingredients to break the yolk.
Add the oil, milk, vanilla and maple syrup. Mix until well combined.
Place the chocolate on a board and using a roller crush into small pieces. Stir into the mixture.
Put the mug into the microwave on high for 3 minutes. Leave to cool slightly before serving. Serve with some vanilla ice cream.