Buttercream, white?????

The very whites are made with crisco, sorry! Or any solid white vegetable shortening, I suppose. You can make yours a little whiter by adding a tiny dab of violet color to it, there is white food color that is titanium dioxide, and also clear vanilla will help!

Can you buy undyed margarine locally?  in Canada it used to come with small patches of the yellow colour, so that you could have it white if you wanted. 

 

Margarine has more or less the same water content as butter--you make a direct replacement for butter, weight for weight.

 

Vegetable shortening comes by different names.

It will make it a bit milder, but I prefer it. If you don't want the taste to change, the titanium dioxide is the best bet. But as long as you use brown vanilla and real butter, it won't be white white. I think it's a good trade-off, myself! I would rather have mine a bit yellow and flavorful, than white and tasteless.

If you use several coats of buttercream, you could use your yummy buttercream as a base coat, and a whiter one as a final coat.

Trex is the UK and Irish equivalent of Crisco, it's in the supermarket. Or you can probably buy Crisco from Amazon or somewhere.
 

I use Italian Mousseline Buttercream. It's slightly off-white, but I think it's fine for a wedding cake. Actually, I find that adding the regular vanilla tempers the color of the butter a bit and makes it look a little whiter. 

 

I use the leftover yolks for chocolate buttercream.

Try adding a drop (and I do mean a drop!) of blue color to your icing. Mix well. You may not get the very white color you get with shortening, but it will be whiter.
 

I think Frytex is the Irish equivalent. It's with the solid fats in the supermarket.

The difference between butter and shortening is not only in taste, but in texture.  It doesn't melt in your mouth and just doesn't taste as rich,  IMO.  I use a mix of butter and cream cheese for my buttercream, which is wonderful but it too, is not white-white.  

 

Normally this is not really a problem, but recently I made a cake with fondant snowflakes and I really wanted it to be white so I got to thinking...I use thin layers of highly  colored frosting to cover the regular buttercream on my colored cakes...why not make a white frosting and use a couple of thin layer of that?

 

So because I don't use shortening I mixed cream cheese and powdered sugar to a frosting consistency and spread it on in two thin layers over my regular buttercream which I had gotten cold and hard in the fridge.  It worked great and because it had cream cheese in it, the flavor blended well with the regular BC..in fact you really could not taste the difference and it gave me the white color I was looking for. HTH!

If you use full fat butter it can be quite yellow. Try using a low fat butter. A farmer said its what the cows eat that determine how yellow it is. You have to find the right brand, my cake supplier in Sydney knows a particular brand, which ofcorse I've forgotten.

I'm a h
I'm a hairdresser by trade, we make bleached yellow hair white by adding violet/purple toner, so this makes total sense lol