I would agree with CorpseQueen on checking the fat. Butter tends to make a denser cake unless you whip the heck out of it, but of course it tastes better than shortening. (Can’t speak to using oil in a yellow cake, haven’t done it.) However, I’d definitely look at your acid/base ratios. It’s possible that you need to adjust by adding a bit of baking soda if you’ve got acids in there such as sour cream, lemon juice, etc.
You can also spend a little more time beating in your eggs; a couple of minutes each on a stand mixer adds a ton of air and helps incorporate the ingredients. Finally, you can try splitting when you add the eggs: beat yolks into butter/sugar and then fold in the whipped egg whites.
© 2011-2017 CakesDecor.com. All Rights Reserved.
DISCLAIMER: Any posts on CakesDecor.com (CD) are posted by individuals acting in their own right and do not necessarily reflect the views of CD. CD will not be held liable for the actions of any user.