Lightly grease 9 holes of a standard muffin tin. Preheat the oven to 180°C fan bake.
Combine all the dry ingredients in a large bowl.
Whisk the milk, egg, butter and vanilla together then pour onto the flour mixture. Gently but thoroughly stir together but don’t over-beat.
Divide the batter between the holes of the prepared tin and bake for about 10 minutes, or until risen and golden.
To finish: Combine the sugar and cinnamon in a bowl.
When cool enough to handle and working with one cake at a time, brush it lightly all over with melted butter then toss in the sugar to coat on all sides. Repeat with the remaining cakes.
