How to Make It
Preheat the oven to 350°. Butter and flour two 9-inch round cake pans.
Sift the flour with the baking powder and salt. In a large bowl, using an electric mixer, beat the butter at low speed until smooth. Add the sugar and beat until fluffy. Add the eggs, 1 at a time, beating well after each addition. Add the vanilla. At low speed, alternately beat in the dry ingredients and the milk in 2 additions. Add the melted white chocolate and beat just until incorporated. Scrape the batter into the prepared cake pans and smooth the surfaces.
Bake the cakes in the center of the oven for 35 minutes, or until golden brown and a toothpick inserted into the centers comes out clean. Let the cakes cool in the pans for 10 minutes, then invert them onto a wire rack and let cool completely.
In a small bowl, using a handheld electric mixer, beat the orange marmalade and the confectioners' sugar into 1 cup of the White Chocolate Buttercream. Set 1 cake layer on a cake plate, right side up, and spread the filling on top. Cover with the second cake layer. Frost the sides and top of the cake with the remaining White Chocolate Buttercream. Garnish with the white chocolate–dipped Candied Orange Peels and serve.
The filling for this cake calls for orange marmalade, but you can also use seedless raspberry or apricot jam. These would work well with the candied orange peel garnish. Edible flowers would also make a lovely decoration.