Preheat oven to 325°F and grease a 9×13 pan.
In a bowl, mix cake mix + egg + melted butter until combined. Press into the pan.
Beat cream cheese, beaten eggs, brown sugar & vanilla. Gradually add powdered sugar and mix until smooth. Stir in chocolate chips.
Spread filling over crust and bake 40–45 min until edges are browned but center is still gooey.
Let cool. Dust with extra powdered sugar & add extra chips if you want!
