1. Preheat oven to 180°C. Line eighteen 80ml (1/3-cup) capacity muffin pans with paper cases. Sift the flour, cocoa powder, bicarbonate of soda and baking powder into a large bowl. Stir in the sugar.
2. Whisk the buttermilk, oil, eggs, food colouring and vinegar in a jug until combined. Make a well in the centre of the flour mixture. Add the buttermilk mixture and stir until just combined.
3. Divide the mixture among the prepared pans. Bake for 20-25 minutes or until a skewer inserted into the centres comes out clean. Transfer the cupcakes to a wire rack to cool completely.
4. To make the cream cheese frosting, use an electric beater to beat the cream cheese, butter, icing sugar and vanilla in a bowl until smooth.
5. Pipe the icing over the cupcakes and top with the sprinkles.