Heat oven to 350 degrees. Grease a 13×9 pan with Clearly by Best Choice cooking spray and set aside. In a mixing bowl place cake mix and the required water, eggs and oil. Beat with an electric mixer on medium speed for 2 minutes.
Pour batter into greased pan and bake for 28 to 30 minutes or until knife inserted in the center comes out clean and the edges are golden. Cool for at least 30 minutes. Once cake is cooled pour gelatin into a bowl and mix in one cup boiling water. Stir contents until gelatin is dissolved. Poke the cooked cake every few inches with the back side of a wooden spoon.
Carefully pour liquid gelatin over the top and cool in the refrigerator for at least an hour.
Meanwhile make the whipped topping. In a large metal bowl pour in chilled whipping cream, then beat with an electric mixer on high until soft peaks form in the cream. Sift powdered sugar over the top of the cream and add vanilla.
Continue whipping the cream on medium speed until powdered sugar and vanilla are evenly distributed. Spread whipped topping over the top of the chilled cake then add chopped fresh berries on top of the cream.
Chill in the fridge until ready to serve.