Preheat oven to 350 degrees
Beat softened butter with either a stand mixer with a whisk attachemnt or a whisk hand mixer.
Add the cake mix, milk and water and beat until smooth.
Add one egg at a time and continue beating until all the eggs are fully incorporated and the batter is smooth. Be sure to scrape the bottom of the bowl and mix to remove all lumps.
Add both boxes of Jiffy corn muffin mix and beat until just combined.
Spray mini loaf pans with non-stick baking spray (I use Pam) and fill the batter halfway up in each compartment.
Bake for 23 minutes on the middle rack. If making muffins, check at 17 minutes.