For the Cake:

1. Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.
2. Melt the white chocolate: In a small saucepan, heat the milk over low heat. Add the white chocolate and stir until melted and smooth. Set aside to cool.
3. Mix the dry ingredients: In a medium bowl, whisk together the flour, baking powder, and salt.
4. Cream the butter and sugar: In a large bowl, beat the softened butter and sugar together until light and fluffy, about 3-4 minutes. Add the eggs, one at a time, beating well after each addition. Stir in the vanilla extract.
5. Combine the wet and dry ingredients: Alternately add the dry flour mixture and buttermilk to the butter mixture, beginning and ending with the dry ingredients. Mix until just combined.
6. Incorporate the white chocolate: Gently fold in the melted white chocolate until fully incorporated.
7. Bake the cake: Divide the batter evenly between the prepared cake pans and smooth the tops. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean. Allow the cakes to cool in the pans for 10 minutes, then transfer to wire racks to cool completely.

For the Coconut-Pecan Frosting:

1. Cook the frosting: In a medium saucepan, combine the evaporated milk, sugar, butter, and egg yolks. Cook over medium heat, whisking constantly, until the mixture thickens, about 5-7 minutes.
2. Add the coconut and pecans: Remove from heat and stir in the vanilla extract, shredded coconut, and chopped pecans. Allow the frosting to cool and thicken further before using.
3. Frost the cake: Once the cakes are completely cool, spread a generous amount of the coconut-pecan frosting over the top of one cake layer. Place the second layer on top and frost the entire cake with the remaining frosting.