Preheat the oven to 350 degrees F (175 degrees C). Grease a 9x13-inch baking dish.
2
Combine cake mix, water, eggs, and oil in a bowl; beat with an electric mixer on medium speed until batter is smooth, about 2 minutes. Pour batter into the prepared baking dish.
3
Bake in the preheated oven until a toothpick inserted into the center comes out clean, 29 to 34 minutes. Cool cake for at least 30 minutes.