Preheat oven to 350°F (175°C). Prepare a 9x13 inch baking pan with a light coating of cooking spray and set it aside.
In a large bowl, combine the cake mix, 240 ml of water, vegetable oil, and eggs. Mix until thoroughly combined.
Pour the batter into the prepared baking pan. Bake for 25 minutes or until a toothpick inserted in the center comes out clean.
Allow the cake to cool. Then, using the handle of a wooden spoon, poke holes over the surface of the cake, spacing them about an inch apart.
In a small bowl, combine 240 ml of boiling water with the strawberry jello mix. Whisk together until the jello is fully dissolved, then pour this mixture evenly over the top of the cake.
Place the cake in the refrigerator and let it cool for 2 hours.
Spread the whipped topping over the cooled cake. Optionally, top with fresh strawberries before serving.