Hi Julia
Welcome to the site.
In order to create pastel coloured buttercream or icing I always use
Sugar Flair concentrated dyes, you need a tiny amount to dye your buttercream but no matter how yellow your buttercream is this should make all the colours you require. As your buttercream is so yellow ensure you are whisking it for long enough to make it go lighter in colour, always sieve your icing sugar to add air to the buttercream and always add a little milk or water to help make a lovely consistency. Here is my tutorial on how I make
buttercream.
View attachment 3525
I created these
two tone cupcakes using Tangerine coloured Sugar Flair concentrated dye.
By using Claret Sugar Flair concentrated food dye I managed to create this pink colour when doing
inside surprise cakes, if you scroll down the tutorial you will see the colour of the cake batter after I added the dyes.
Sugar Flair dyes can be bought from any cake store or online at Amazon or other cake sites, the supermarket brands tend to be watered down and do not give the results you require, they can also make a lot of mess too.
I recently made this My Little Pony Cake and all the pastel colours were made using Sugar Flair dyes, these same colours can be used to dye buttercream and create the same results. Add tiny bits of colour using a cocktail stick and swirl it through your buttercream, mix in using your electric whisk, add the colour in stages until you reach your required colour, remember a little goes a long way. The cake has been covered in white fondant that was dyed party green. The waterfall is baby blue in colour and the flowers are tangerine, lemon, grape and Christmas red.
View attachment 3526 View attachment 3527
You will see that behind the blue pony on the left there is some buttercream grass, I used the same party green sugarflair dye to dye this as I did to dye the icing.
Christmas Red sugar flair dye makes a lovely girlie pink colour too if the claret is too dark for you.
If you need anything further please let me know.
Good Luck!
:thumbs: