1. Add Extra Eggs
This is hands down the best approach to make those cake mixes taste moister and richer.
Most cake mix directions call for simply one or two eggs, but including an extra egg permits the cake to bake up with a more dense, velvety texture.
The extra egg adds more structure and fat to the batter. Don’t forget the yolk! It gives the cake more richness.
For best results, use large eggs and beat them thoroughly until smooth after adding the cake mix and other wet ingredients.