Cake - 3½ cups cake flour - ½ cup unsweetened cocoa (not Dutch process) - 1½ teaspoons salt - 2 cups softened butter - 2¼ cups granulated sugar - 4 large eggs - 1½ teaspoons vanilla - 1¼ cup buttermilk - 2 teaspoons baking soda - 2½ teaspoons white vinegar.

Milk chocolate and Ferrero Rocher filling - 15 Ferrero Rochers, crushed - 200g Lindt milk chocolate, finely chopped - 1 tablespoon unsweetened alkalized cocoa powder - 2/3 cup heavy cream

Nutella Ganache - 1 cup Nutella - 1 cup heavy cream