For the Cake
Preheat oven to 350 F.

Grease the bottoms of two 6 inch round cake pans. Line bottoms of pans with parchment paper; grease and lightly flour pans and set aside.

In a medium saucepan, cook and stir the white chocolate over low heat until melted.

In a medium bowl, combine flour, baking powder, and salt and set aside.

In a large bowl, beat the butter with an electric mixer on medium to high speed for 30 seconds. Gradually add the sugar, beating until combined. Add eggs one at a time, beating after each addition. Beat in the vanilla.

Alternately add flour mixture and milk to butter mixture, beating on low speed after each addition just until combined. Beat in melted white chocolate just until combined.

Spread batter in the prepared cake pans. Bake about 30 minutes or until a toothpick inserted in the centers comes out clean. Cool cake layers in pans on wire racks for 10 minutes. Remove layers from pans. Peel off parchment paper. Cool completely on wire racks.

Assembling the Cake
Use a long serrated knife to cut each cake layer in half horizontally. Place one layer, cut side up, on a serving plate.

Spread with one-third of the filling. Top with the second layer; spread with one-third of the filling. Top with the third layer; spread with the remaining filling. Top with the fourth layer, cut side down.

Frost cake with frosting and decorate with white chocolate shavings and blueberries.