Fat

No matter which method you use to incorporate the ingredients into the fat to make a butter cake, the fat always influences the cake’s tenderness and its ability to stay fresh. Whether liquid or solid, fat particles disperse evenly throughout the other ingredients, and though fat may appear to dissolve into them, it really suspends itself among them. The result is a tender cake because the fat particles never cohere to one another tightly. Since the fat coats the other batter particles, it also retards the escape of moisture during baking and prolongs the cake’s eating quality. That is why I usually advise against refrigerating butter cakes. When a cake is chilled, its high fat content tightens its texture, affecting its eating quality and taste so the cake doesn’t seem to be tender or melt in your mouth at all. This is easy to understand when you consider the consistency of cold butter.