I have a white cake recipe that makes a wonderful 9" cake. It calls for 6 egg whites. Can I make a yellow cake by adding the yokes? And do I need all 6 eggs?
One of the bakeries I worked at added yellow food color to the white cake to make yellow. Never fail formula.
I think the addition of lemon extract/zest to the vanilla and almond make yellow--along with the yolks.
There's no hard and fast rules.
But if you add an additional 6 yolks to the same formula you might create an imbalance with the chemistry of the cake. So kinda think about balancing the quantity of egg might be an idea.
Figure what you think 6 egg whites equals in how many whole eggs.
Or just add some food color.
roughly: 2 egg whites = 1 whole egg.
so use only 3 whole eggs
if using oil, might even substitute a nice yellow butter
B U T
remember: scratch baking is chemistry.
will change in fat content (yolks have fat, whites don't) affect the batter in way that could cause failure of batter to work properly?
ditto to subbing butter for oil in scratch recipe.