Preheat the oven to 325 degrees. Spray a 9×13 baking dish with nonstick cooking spray. Set aside.
In a large mixing bowl, combine the two cake mixes, eggs, oil, milk, and 1 cup of cold water. Using a hand mixer or stand mixer, beat until no lumps appear. It will seem thin, but this is what you want.
2 boxes Cake Mix, 6 large eggs, 1 cup vegetable oil, 1 cup water, 1 cup milk
Pour into your prepared baking pan and bake for 50-60 minutes or until a toothpick inserted into the middle of the cake comes out clean and the top of the cake is golden brown.
Remove the cake from the oven and place the baking pan on a wire rack. Do not remove the cake from the pan. Let the cake cool in the pan for about 20 minutes.
Using a wooden spoon with a round handle to poke holes in rows about 1 inch apart in the cake. You want to push the handle about 3/4 of the way through the cake.
Add the jello and boiling water to a medium mixing bowl and stir until the jello is dissolved. Place the jello in a pourable container such as a glass or plastic measuring cup. Slowly pour the jello over the top of the cake. First pour it into each of the holes and then pour any remaining liquid over the surface of the cake.
1 cup water, 3 ouces Cranberry Jello
Cover the cake with plastic wrap and place in the refrigerator for 4 hours or until the jello is set.