Preheat oven to 350 degrees F. Line 2 large baking sheets with parchment paper and set aside.
Using an electric mixer, mix ingredients on low speed for 30 seconds, then on medium speed for a minute. The batter will be thick; just make sure that all of the cake mix has been incorporated.
Fold in your mix-ins.
Drop by rounded tablespoons onto a baking sheet. Press down slightly with your fingers to flatten.
Bake in the preheated oven for 11-12 minutes. Allow to cool for a couple of minutes before transferring to a cooling rack.
Notes
I added half a cup of raisins and half a cup of chocolate chips - because everything's better with chocolate!
Once cooled, store in a tightly sealed container for up to 6 days.