Preheat your oven to 350°F (175°C). Grease and flour a 9x13-inch baking pan.

In a large mixing bowl, combine the yellow cake mix, eggs, water, and vegetable oil. Beat on medium speed for about 2 minutes or until well combined.

Pour the batter into the prepared pan and bake for 30-35 minutes or until a toothpick inserted in the center comes out clean.

Once the cake is baked and has cooled for about 10 minutes, grab a fork and poke holes in the cake about an inch apart.

Make sure those holes are deep enough to hold all the delicious cream filling.

While the cake cools, gently mash the fresh blackberries with a fork until juicy but not pureed.

Pour the mashed berries into the holes of the poke cake, spreading them evenly.

In a separate bowl, whip the heavy cream until it begins to thicken.

Gradually add in the melted white chocolate and powdered sugar, continuing to whip until soft peaks form.

Be careful not to overbeat, or you might end up with butter instead of cream!

Spread the luxurious white chocolate whipped cream over the poke cake, ensuring you cover all the blackberry holes.

Create a dreamy topping.

Cover the cake and refrigerate for at least an hour.

Just before serving, garnish with fresh blackberries.