Preheat your oven to 350°F (175°C). Grease your baking pan with non-stick spray or line it with parchment paper for easy removal.
In a large mixing bowl, combine the yellow cake mix and vanilla pudding mix. Add the water, vegetable oil, and eggs. Mix everything together until smooth and well combined.
Fold in the chocolate chips (or your choice of chips) using a spatula. Make sure they are evenly distributed throughout the batter.
Pour the batter into the prepared baking pan, spreading it evenly. Bake in the preheated oven for 20-25 minutes or until the edges are golden and a toothpick inserted in the center comes out clean.
Once baked, remove the pan from the oven and allow the cookie bars to cool in the pan for about 10-15 minutes. Then, transfer them to a cooling rack to cool completely before cutting into squares.
