1. Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking dish.
2. In a large bowl, combine the cake mix, water, oil, and eggs. Beat on medium speed for about 2 minutes until smooth.
3. Pour the batter into the prepared dish and bake for 30-35 minutes or until a toothpick inserted into the center comes out clean.
4. Allow the cake to cool for 15 minutes. Using the handle of a wooden spoon, poke holes all over the cake about an inch apart.
5. In a bowl, dissolve the strawberry gelatin in boiling water. Add cold water and stir until well blended.
6. Carefully pour the gelatin mixture over the cake, ensuring it seeps into the holes. Refrigerate for at least 2 hours.
7. In a chilled mixing bowl, whip the heavy cream until soft peaks form. Add powdered sugar and vanilla extract, whipping until stiff peaks form.
8. Spread the whipped cream evenly over the chilled cake. Top with sliced strawberries, arranging them in a beautiful pattern.
9. Refrigerate the cake for an additional hour before serving to let the flavors meld together.

Pro Tip: Use a serrated knife to slice the cake for clean, neat pieces that showcase the beautiful layers.