Creaming is a baking technique that involves combining a softened fat (usually butter, but not always) and sugar until it becomes voluminous, fluffy and, well, creamy. It’s most often done with a stand mixer (such as a KitchenAid).
What’s the point of creaming butter and sugar? Can’t you just stir the two together?
Creaming butter and sugar accomplishes an important effect: It incorporates air into the final mixture to help leaven your baked goods and create a tender crumb. To get all science-y, the tiny sugar crystals cut through the softened butter and leave air pockets in their wake, which then capture the gases released by the leavener in the recipe and adds loft to your cookies (or cake, or quick bread).
If you skip the creaming step, the recipe will most likely turn out heavy and dense instead of light and tender. But if you over-cream the butter and sugar, you’ll likely end up with something gummy and dense. If you know what visual cues to look for, you’ll end up with perfectly creamed butter and sugar every time.
It’s all about buttah
Proper creaming is a delicate balance of mixer speed, timing and butter temperature, but I would argue that the most important factor of the three is the butter. You want it to be softened…but not too soft (and not melted). If the butter is too cold, the mixture will be dense. If it’s too soft, it will be oily. Neither is good for a cookie or cake.
When you press a finger into the butter, it should give easily but still be solid and maintain some structure. There are about a million hacks to soften butter fast, but none are as reliable as simply taking the butter out of your refrigerator 30 to 60 minutes before you want to use it.