This is a fabulous base for covering big cakes. It may seem odd at first to add shortening to icing, however, for perfectly frosted, big American-style cakes, this variety is the only answer for me. The butter adds flavour, but if you prefer an ultra white buttercream, you can replace the butter with more vegetable shortening. This recipe makes enough buttercream to cover a three-layer 30cm cake – enough to fill between the layers and cover.
Put the butter, vegetable shortening and vanilla into the bowl of the stand mixer fitted with a paddle attachment. Turn the machine on to a medium speed and mix together for a good 5 minutes. Halfway through the mixing process, scrape down the sides of the bowl using a spatula. You can also mix this buttercream with a hand-held electric whisk, but you will need a very big bowl, and when it comes to adding the icing sugar it can get pretty messy.
Add one third of the icing sugar to the butter mixture. To stop the icing sugar from flying everywhere, cover the machine with a tea towel, taking care not to get it anywhere near the paddle attachment. This technique prevents icing sugar from going all over the kitchen, but you can remove the tea towel when the icing sugar is all mixed in. Add the icing sugar, little by little, until it is all mixed in. Start with a very slow speed and when the mixture starts to combine, increase the speed to high. Then add the milk and beat until well combined, scraping down the sides of the bowl with a spatula. If you prefer your buttercream to be thin, you can add more milk, tablespoon by tablespoon, mixing well between each addition until it reaches the consistency you require.
The buttercream is now ready to use and will keep at room temperature for 3 days, or up to 2 weeks in the fridge covered with cling film.
When you’re ready to use the prepared buttercream, half-fill a piping bag to frost your cake. Once you have finished frosting the cake, it will take 30–45 minutes to form a relatively firm crust.
© Lorraine Pascale, 2017. Images: © Myles New, 2017.