Hi, I want to make a birthday cake and to colour the frosting black. I don't know how to make black frosting - can you help please?
It is quite difficult to get a true black colour on cake frosting and many times they turn out a deep purple rather than black. However there are a couple of things that can help to get a dark, almost-black colour. The first is to use a gel paste rather that liquid food colour as it is much more concentrated and you will generally get a stringer colour when using pastes.
The second its to use a chocolate frosting as it already has a dark base colour. Using a white or pale frosting base will result in either a grey-coloured frosting or you will need to add so much food colour to make the frosting black that the food colour will make the frosting taste bitter. You may have a favourite chocolate buttercream recipe that you can use, or try the All-Purpose Chocolate Icing from Domestic Goddess (p195), beating in the food colour a little at a time after the vanilla and rum have been added.
If you are wanting to colour ready to roll (Regalice/rolled fondant) icing then we would suggest looking for icing that is already coloured black as this will always have a much truer black colour than you can achieve at home. Some UK supermarkets sell boxes containing 4 small packages of pre-coloured icing, which includes black, Wilton sells a "natural" colours pack which includes black. You can also buy chocolate-flavoured ready to roll icing from cake decorating suppliers which again will be easier to colour with black if a large quantity is needed.