Preheat oven to 350°F (175°C). Grease and flour two 8-inch cake pans.

In a large bowl, whisk together flour, sugar, baking powder, and salt.

In another bowl, cream together softened butter and melted white chocolate until smooth.

Beat in eggs one at a time, then stir in vanilla extract.

Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined.

Divide the batter evenly between the prepared cake pans.

In a small saucepan, combine raspberries and sugar. Cook over medium heat until raspberries break down and the mixture thickens slightly. Let cool.

Gently swirl dollops of the raspberry mixture into the cake batter in each pan.

Bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean.

Let the cakes cool in the pans for 10 minutes before inverting them onto a wire rack to cool completely.

In a large bowl, beat together softened butter and powdered sugar until smooth.

Beat in the melted and cooled white chocolate, heavy cream, and vanilla extract until light and fluffy.

Place one cooled cake layer on a serving plate. Spread a generous amount of frosting over the top.

Top with the second cake layer and frost the entire cake.

Decorate as desired, perhaps with fresh raspberries or white chocolate shavings.