Preheat your oven to 350°F (175°C). Prepare the white cake mix according to the package instructions, pouring the batter into a greased 9x13 inch pan. Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean. Once done, allow the cake to cool in the pan for about 1 hour on a wire rack.

Once the cake has cooled completely, poke holes in the cake at 1-inch intervals using the handle of a wooden spoon. Ensure the holes are deep enough to allow the Jell-O to soak in.

In a medium bowl, prepare the Strawberry Jell-O by mixing the contents with 1 cup of boiling water. Stir until completely dissolved, then add in ½ cup of cold water. Repeat for the Blueberry Jell-O in a separate bowl.

Fill each hole with the prepared Jell-O, alternating between strawberry and blueberry. Allow the Jell-O to fill the holes generously.

Cover the cake with plastic wrap or aluminum foil and refrigerate for at least 3-4 hours, ideally overnight.

Once chilled, remove from the refrigerator and gently spread the whipped cream over the top. Optionally add fresh berries or sprinkles.