There’s a couple things I like to do: the first is to beat the frosting for about five minutes. This will lighten the color quite a bit. The second is to add a little white food coloring or the slightest bit of purple food coloring (it acts like purple shampoo and cancels out the yellow).
The keys to this kind of buttercream are threefold: first, make sure to sift your powdered sugar to get rid of the clumps; second, add a few tablespoons of heavy whipping cream; third, after the ingredients are combined, turn your mixer to medium-high speed and mix for about five minutes – this will lighten the texture and color of the frosting.
You’ll actually want to add the chocolate while it’s still warm in a slow and steady stream to temper the chocolate.
I always run my AC a bit more when I’m frosting cakes and I always make more to chill them between the crumb coat and final coat of frosting. I also chill the cakes after I make them. Don’t let them sit at room temperature too long.
Buttercream! I’ve never used fondant. I’ve tasted it and don’t love it, so I’ll never use it. I only make what I like to eat!