1. Preheat the oven to 350°F using an oven thermometer to verify temperature. Lightly coat a 13-by-9-inch metal cake pan with cooking spray using a pastry brush for even coverage.
2. Pour the yellow cake mix into a large mixing bowl. Use a silicone spatula to break up any clumps in the dry mix before adding wet ingredients.
3. In a medium glass mixing bowl, combine 1 cup cold water, vegetable oil, and eggs using a wire whisk. Whisk vigorously for 30 seconds until the mixture is fully emulsified and uniform in texture.
4. Pour the wet ingredients into the large bowl with cake mix. Use an electric hand mixer on medium speed to blend for 2 minutes, scraping down the sides with a rubber spatula halfway through.

5. Transfer the batter to the prepared cake pan using a silicone spatula to spread evenly. Bake on the center oven rack for 22-25 minutes, checking doneness with a toothpick that should come out clean.

6. Place the baked cake on a wire cooling rack for 30 minutes. Use a wooden skewer to poke holes across the entire surface, spacing them about 1 inch apart.

7. In a medium heatproof bowl, dissolve raspberry gelatin in 1 cup boiling water by whisking continuously for 2 minutes. Stir in remaining 1 cup cold water using a long-handled spoon until fully incorporated.

8. Slowly pour the gelatin mixture over the cooled cake using a liquid measuring cup for control. Cover the pan tightly with plastic wrap and refrigerate on a level shelf for 6-12 hours.

9. For the whipped cream, place white chocolate chips in a medium glass bowl. Heat 1/2 cup heavy cream in a microwave-safe measuring cup for 30-45 seconds until steaming, then pour over chocolate.

10. Let the chocolate mixture sit undisturbed for 2 minutes, then whisk vigorously with a small wire whisk until completely smooth. Cover with plastic wrap pressed directly on the surface and chill for 6-12 hours.

11. In a stand mixer fitted with the whisk attachment, combine chilled chocolate mixture with remaining 1 cup cream and vanilla. Whip on medium-high speed for 2-4 minutes until stiff peaks form, scraping the bowl with a silicone spatula as needed.

12. Spread the whipped cream over the chilled cake using an offset spatula for smooth application. Garnish with fresh raspberries arranged decoratively using clean kitchen tweezers or fingers.