Getting ready to make a birthday craved car cake, the cake is basically  a buttermilk ....trying to decide  what flavor to make the filling, can't  have any bits and pieces of real fruit,chips or nuts......and they " don't  want something  very sweet"....I'm also using fondant  and modeling chocolate  on it......(I haven't  baked a cake in years as I got hooked on cookies, so am really nervous) thank you

use a lemon curd and swiss meringue buttercream or french vanilla buttercream aka cooked flour, ermine, wilton's french buttercream -- gotta keep it fridged though but these are all 'less' sweet -- even a raspberry filling is tart and a good foil to the sugar involved --

oh wait -- i've never covered the french vanilla buttercream with fondant so scratch that idea -- but swiss mbc would work great 

Thank you, was thinking of just adding raspberry and  lemon to the buttercream.....since it's been so long since I've  carved a cake, I don't  think I want to add a curd or anything slippery...

I got some wedding bouquet and the ck brand of  cream bouquet  but I think with the molding chocolate  and fondant that it might be too sweet...

in Australia, we pretty much all do mud cakes for carved cakes. The 66 Mustang was white choc mud , with traditional Australian buttercream (just icing sugar, butter, a touch of water, vanilla and food colouring). I always ganache my cakes too as it is nice and firm for fondant. I also don't refridgerate any of my cakes as they are shelf stable (no milk in the buttercream and the cream is boiled in the ganache). Also due to the size of the cake itself, it can't be refridgerated in normal fridges.

Kylie cake thank you, I do have the blue prints for the mustang...and my icing is all butter also....it's what was recommended on the dvd that I ordered....along with the buttercream. Do you use a mud cake recipe  from on CC ?

no i don't. i use one from the book called "the essential guide to cake decorating", published by Lifetime Distributors.