Lightly grease 4 medium sized microwaveable mugs.
Whisk together the sugar, buttermilk, oil, egg and vanilla until smooth.
Whisk in the flour, bicarbonate of soda and salt until just combined.
Pour the mixture into the mugs.
Microwave 1 mug at a time for 1-2 minutes until risen and cooked through.
Cool and decorate.