Preheat the oven to 350°F (175°C). Grease and line two 9-inch cake pans.
In a large bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
Cream the butter and sugar together until light and fluffy. Add the eggs one at a time, then mix in vanilla.
Stir in the buttermilk, sour cream, and melted white chocolate. Mix until well combined.
Gradually add the dry ingredients to the wet, mixing just until incorporated.
Gently fold in the raspberries with a spatula—don’t worry if they break up a bit.
Divide the batter between the prepared pans and bake for 25–30 minutes, or until a toothpick comes out clean.
Cool the cakes in the pans for 10 minutes, then turn out onto wire racks to cool completely.
Frost, layer, and garnish with white chocolate shavings and more raspberries. Slice and serve!