In a large bowl, beat together the softened cream cheese and butter. Add egg and vanilla. Continue to mix until fluffy.
Add the cake mix and beat until you have a smooth batter. Cover the bowl and place in your refrigerator for 2 hours. When you are ready to bake, preheat your oven to 350 degrees F.
Spoon the batter on your prepared baking sheet. Bake for approximately 10 minutes or until edges are starting to crack, getting firm and middle no longer looks wet to stay chewy, or firming all the way across to become crispy.