Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.
In a large bowl, whisk together flour, baking powder, and salt.
Beat the butter and sugar until light and fluffy. Add the eggs one at a time, mixing well after each. Stir in the melted white chocolate and vanilla extract.
Gradually add the dry ingredients alternately with buttermilk until combined.
Pour the batter into the prepared pans and bake for 25-30 minutes, or until a toothpick comes out clean.
In a saucepan, combine the cream, sugar, egg yolks, and vanilla. Cook over medium heat, stirring constantly, until thickened. Stir in the coconut, pecans, and butter.
Allow the cakes to cool, then layer them with the coconut-pecan filling in between and on top.