Preheat oven to 350 degrees. Spray a 9X13 inch baking dish with nonstick cooking spray.
Prepare the cake according to box instructions. Pour into the prepared baking dish and bake until a toothpick inserted in the center comes out clean. Set the pan on the wire baking rack and cool for 15 minutes.
Meanwhile, in a medium bowl, whisk together jello and boiling water, until jello is completely dissolved.
Using the end of a wooden spoon, poke holes into the cake, every inch. Carefully pour jello mixture evenly over top of the cake. Wrap and refrigerate for 1 hour.
Spread pie filling evenly over top of cooled cake. Using the back of a rubber spatula, gently press the pie filling into the holes. Spread with a cool whip over the top. When ready to serve, top decoratively with sliced strawberries and serve!