Cupcakes: Preheat oven to 190°C or 170°C fan-forced. Beat butter with an electric mixer until smooth, add Chelsea Caster Sugar and beat until light and fluffy. Add eggs and mix well. Add the sifted flour, milk and vanilla, beat until smooth. Place paper baking cases in a cupcake tin, spoon in mixture until they are about 2/3 full (don't overfill or they will form peaks). This recipe makes 24 cupcakes so you might need to do this in two batches. Bake for 20 minutes until golden or until they spring back when lightly pressed. Turn out onto a wire rack to cool while you prepare the icing.
Buttercream Icing: Beat the butter until it is pale and fluffy. Sift in the Chelsea Icing Sugar, add the vanilla essence and milk until you have a light, fluffy mixture. Add extra milk if you need a softer consistency. Spread or pipe icing over cupcakes and top with decorations as desired.