4cups powdered sugar*also known as icing sugar or confectioner's sugar
2Tbspcustard powder
5Tbsphot water
Instructions
In a stand mixer fitted with a paddle attachment, cream the butter, powdered sugar and custard powder on medium-high speed until pale in color.
Using a plastic baking spatula, scrape down the sides of the bowl and add the hot water. Beat the mixture on medium speed until the filling icing is light and fluffy.