While your cake is cooling, go ahead and whisk your raspberry gelatin mix into the boiling water in a large measuring cup or small bowl.
Add in the cold water and whisk until all of the Jello powder is fully dissolved. This may take a few minutes.
Once your cake has cooled, use a fork to poke holes all over the top of the cake. Try to space your holes about 1-2 inches apart.
Next, pour your Jello mixture slowly and evenly over the top of the cake and let it cool completely.
Use a spatula to spread the Cool Whip or other whipped topping over the top of your raspberry poke cake.
Once you've spread your whipped topping over the cake, cover your poke cake with plastic wrap or a lid that fits your cake pan, and let it chill in the refrigerator for at least a few hours or even overnight.
Once fully chilled, slice up and serve your raspberry poke cake with a pile of fresh raspberries!