Non-Crusting American Buttercream
I like to use this buttercream recipe most often, even when using it as the finish on a buttercream cake. It has no shortening in it which means it won't be entirely "white". It will be more of a cream color. This recipe works great as the layer of icing underneath fondant if you’re trying to achieve sharp edges, because it will harden when you chill your cake before adding your layer of fondant.
Cream butter in mixer with beater blades or flat blade (NOT whisk), on medium for 2 minutes
Add extract and water and beat on low until incorporated
Gradually add sugar, beating on LOW (very important to avoid air bubbles) until just mixed