Preheat your oven to 350°F.

Line a 9×13 inch baking pan with parchment paper for easy cleanup.

In a large bowl, stir together the cake mix, beaten eggs, and melted butter until the dough is well blended. The mixture will be thick.

Fold in the chocolate chips or any other mix-ins you'd like.

Spread the dough evenly in the prepared pan, pressing it out to the edges.

Bake for 20 to 25 minutes, or until the edges are lightly golden and a toothpick comes out clean from the center.

Let the cookies cool in the pan for about 10 minutes. Cut into squares and serve warm or at room temperature.