This buttercream is great to use when you have warm weather, or when you plan on having your cake out for a long time. It stands heat well and tastes delicious, with its addition of rum. I recommend it mostly with yellow spongecake.
Chocolate Icing
Melt some chocolate, melt some butter, and you have a delicious icing for your cakes. Done right, this coating is good enough on its own. It's my personal practice that anytime a recipe has a flavouring option, I'll default to the one that uses rum, bourbon, cognac, or any other spirit. This recipe should be enough to coat a two-layer cake.