Once your butter and sugar mixture is light and fluffy, it's time to add the eggs. Eggs should always be added one at a time because fats and liquids do not mix together well. While egg yolks are fatty and blend in relatively quickly, egg whites are not, and when you add them to your creamed butter and begin to stir them in, you will see that they resist incorporation. A minute of vigorously whisking the whole egg into the batter will break up the egg and allow it to be properly mixed in. It is also simply much easier to work with the eggs one by one, rather than having a huge amount of liquid sloshing around in the bowl. The batter will look smooth and shiny once the eggs are added. If it curdles a bit, don't worry about it. That can happen because of the wet to dry ratio or because the ingredients were at slightly different temperatures. Just keep going.
Break all your eggs into a small bowl and add them to the creamed butter one at a time. Then get your bowl of dry ingredients, because it's time for the next step.
[Photo by Nicole Weston]










