I mentioned in my last post that someday I'd like to do a comprehensive side-by-side comparison of all things buttercream. Realizing that I may not get to it right away, I wanted to give you one all-important tip to consider when making buttercream icings.
It all has to do with the temperature of the butter.
Recipes for buttercream usually call for "softened" butter, or "butter at room temperature". More recently, I've noticed that recipes are getting more specific and list "butter, at cool room temperature" or "butter, softened but still cool". Confused yet?
It's simple really. When using butter for cooked buttercream icings (meringue icings, French buttercreams, or boiled icings), the butter cannot be too warm, or the frosting will not set up properly and will probably stay a liquidy mess, not worthy of any cupcake. (There are ways to try to remedy this if this should happen .)
For this reason, you should never, ever, microwave your butter to soften it - no matter how quickly you need the softened butter. The microwave heats the butter unevenly and you'll have some cool spots, and other areas that are melted. Your buttercream will reject you if you do this.
So how can you tell if the butter is ready? Take a piece of butter between your thumb and finger and squeeze it a little. You should be able to make an impression in the butter with your fingers, but it should still provide some resistance. The butter should feel more waxy than greasy. If the butter is still too cool (too hard to press into), wait a while longer. Sometimes I'll flatten each piece with my hand before it goes into the mixer. If it gives way without any resistance, the butter is too soft. Get it back into the refrigerator for a few minutes until it passes the test.