The success of most any cake depends on the temperature of your ingredients. Too warm and the batter will be thin, which will make a cake that's gummy and dense. Too cold and the batter will be heavy and curdled, giving the cake a coarse and muffin-like crumb. These problems can be avoided altogether simply by paying attention to the temperature of your butter, milk, and eggs. With those details squared away, it's easy to whip up a simple three-egg vanilla cake that's fluffy, tender, and perfectly moist.