Preheat oven to 180C. Line a 12 x 1/3 cup capacity muffin tin with cupcake patties.
Using an electric mixer on medium setting, mix all cupcake ingredients except the milk. Gradually add the milk and mix just until smooth.
Divide the mixture across the 12 cupcake patties. A generous tablespoon should be sufficient. The mixture should triple in size once baked.
Bake for 15-20 minutes or until cake skewer inserted into the centre comes out clean. Allow to cool.
TO MAKE BUTTER CREAM ICING: Beat butter with icing sugar using an electric mixer. Beat in vanilla essence and milk until smooth, adding extra milk or icing sugar if necessary. Add orange food colour. Use a piping bag to decorate swirls onto cooled cupcakes or use a spatula to slather generously over each cupcake. Sprinkle with coloured sprinkles.