In a medium saucepan, heat 2 cups of frozen raspberries over medium heat until they begin to break down, about 5 minutes. Mash the raspberries and sieve the mixture to remove seeds. Return the raspberry puree to the saucepan, add 1 cup of granulated sugar and 2 tablespoons of cornstarch, and stir until thickened, approximately 5 minutes. Set aside to cool.

In a mixing bowl, whisk together 2 cups of cake flour, 1 teaspoon of baking powder, 0.5 teaspoon of baking soda, and 0.25 teaspoon of salt. In a separate large bowl, cream 0.5 cup unsalted butter with 1 cup of sugar until light and fluffy. Add 4 egg whites and 2 teaspoons of vanilla bean paste, mixing well. Gradually incorporate the dry ingredients and 1 cup of buttermilk, mixing until just combined.

Preheat your oven to 350°F (175°C). Grease a 9x9 inch cake pan with butter and pour in the batter, smoothing the top. Bake for 35-40 minutes or until a toothpick inserted in the center comes out clean. Allow the cake to cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.

In a mixing bowl, whisk together 0.5 cup of half & half, 0.25 cup of sweetened condensed milk, and 1 teaspoon of vanilla extract. Once the cake has cooled, use a skewer to poke holes evenly across the top of the cake. Pour the vanilla milk mixture over the cake, allowing it to soak in.

In a mixing bowl, whip 0.5 cup of softened unsalted butter until fluffy, about 3-4 minutes. Add 8 ounces of cream cheese and 6 ounces of melted white chocolate, mixing until combined. Gradually sift in 2 cups of powdered sugar and mix until smooth and creamy.

Carefully cut off the top layer of the cake to create a flat surface. Spread a layer of raspberry jam on top of the soaked cake, then generously frost the cake with the white chocolate cream cheese frosting. Decorate with swirls of additional raspberry jam and fresh raspberries.