Creaming means beating a fat (such as butter) with another ingredient (usually sugar) until it becomes soft and smooth. Creaming butter and sugar together creates tiny little air bubbles which help to expand the overall volume of the mixture. When adding other ingredients into the creamed batter be sure to not overwork it otherwise the air bubbles will be destroyed thus ruining the effect of the creaming.
When creaming, whip or beat the softened (NOT melted) butter alone until it expands, lightens in color, and sightly expands. This will take about 3-4 minutes in a stand mixer. Do not rush this step, thoroughly creaming the butter aerates it which adds to the lightness of the finished product. Once the butter is nicely creamed, add in the sugar and beat until well combined, light, and fluffy. At this point, the mixture may be referred to as a “batter“.