Beat the Tararua Butter until smooth, pale and fluffy. Gradually add the Chelsea Icing Sugar, half a cup at a time. Add the vanilla essence (or other flavoured essence and/or colouring of your choice), with enough of the hot water to make a creamy mixture, beating between each addition until fluffy. Pipe onto cooled cupcakes or spread over a cooled cake.
Note: When adding food colouring add it a few drops at a time and make sure you mix it in otherwise you might end up with a brighter result than you desire.
Variation: Replace icing sugar with Chelsea Berry Flavoured Icing Sugar or Chelsea Chocolate Icing Sugar.