Welcome to the Cake Decorators Q&A
Alternative fillings to buttercream
Can anyone suggest alternative fillings to buttercream (too sweet) for different flavoured sponge cakes which will be covered with sugar paste?
Meringue type buttercreams are less sweet and much smoother than the traditonal butter icings. I use Italian meringue which uses egg whites and boiled sugar. There are lots of recipes online. Swiss meringue is also less sweet .... again, many online recipes. Egg white powder or Merrie whites powder can be used instead of fresh whites. If you want to avoid buttercream altogether, how about a semi sweet ganache filling? Have a look at Paul's ganache tutorial in the free tutorial section. You could also use ingredients such as jam, nuttella, peanut butter ( allergies permitting). Tinned fruit fillings or fruit which has been preserved in jars should all be shelf stable enough. For more ideas have a peek here and click on threads most appropriate to you:
Fresh dairy fillings such as cream cheese, fresh cream or whisked cream have to refrigerated and not suitable for the type of cakes used in the tutorials. Curd fillings which use fresh egg yolks also require refrigeration.
These are just a few ideas. Hope they help.