Preheat the oven to 350°F (175°C). Prepare a 9×13-inch baking dish by coating it with nonstick cooking spray, preferably the type that contains flour.
In a mixing bowl, combine the yellow cake mix with the melted salted butter and beaten eggs. Using an electric or stand mixer is recommended for easier blending, as the batter will be quite thick.
Fold the semi-sweet chocolate chips into the batter, mixing until evenly distributed.
Transfer the thick batter into the prepared baking dish. To help spread the batter evenly, lightly coat your hand with nonstick cooking spray and use it to press the batter into the pan.
Bake in the preheated oven for 20 to 25 minutes. The bars are done when they have puffed up and the edges are golden brown.
Allow the cookie bars to cool completely before cutting into squares.