One of the best ways to improve your baking is to make sure you’re not under-creaming or over-creaming your butter and sugar.

Here’s a quick overview:⁠⁠

• Perfectly creamed butter has lightened in color and has peaks and valleys in its texture, giving it that ‘fluffy’ appearance. The sugar appears to be dissolved, but when you rub the mixture between your fingers you’ll still feel the sugar granules.⁠
• Under-creamed butter and sugar looks darker in color with a visible heavy and gritty texture from the unincorporated sugar. It doesn’t allow enough air to become incorporated into your batter or dough. This can lead to heavy cake that doesn’t properly rise or dense cookies.⁠
• Over-creamed butter and sugar adds in too much air and alters the final texture… typically to be more gummy and dense. Sometimes over-creaming can produce cakes, cupcakes, or cookies that collapse upon baking or upon cooling if the mixture is well and truly over-creamed (where it looks like curdled milk).⁠