Preheat your oven to 350°F (175°C).

In a large mixing bowl, combine the yellow cake mix, water, vegetable oil, and eggs. Whisk until smooth and well blended.

Pour the batter into a greased 9x13 inch baking pan.

Bake for 30 minutes or until a toothpick inserted in the center comes out clean. Let it cool completely after baking.

In a medium bowl, dissolve the Jello in 1 cup of boiling water. Stir well until fully dissolved.

Add 1 cup of cold water to the Jello mixture.

Once the cake is completely cooled, use a fork to poke holes all over the top.

Carefully pour the Jello mixture over the top of the cake, ensuring it fills the holes.

Cover the cake with plastic wrap and place it in the refrigerator for at least 4 hours.

Once the Jello is set, spread the Cool Whip evenly over the top of the cake.

Slice into squares and serve with fresh fruit on top if desired.