Preheat the oven to 350°F. Spray 12 x 18 in. sheet cake pan with vegetable pan spray.
In the medium bowl, combine flour, baking powder, and salt.
In the small microwave-safe bowl, heat milk until hot, but not boiling.
Add white chocolate; stir until chocolate melts. Add vanilla, and set aside
In the large bowl, beat butter and sugar with the electric mixer until light and fluffy.
Mix the butter and sugar in the electric mixer until it becomes fluffy. Add eggs, one at a time, mix well.
Add the flour mixture alternately to the melted chocolate, mix them well until it is combined. Pour into prepared pan.
Bake for 12-16 minutes or until the toothpick placed in the middle comes out. Refrigerate them for 10 minutes in the pan.
Slice the cooled cake into quarters. Spread the preservative raspberry between the layers of slice cake.
Decorate with white chocolate curls and fresh raspberries. Refrigerate them until ready to serve.