This unique version needs dark chocolate, butter, brown sugar, eggs, flour, vanilla, and a Milka Toffee Whole Hazelnuts 300g bar. Melt butter and chocolate, then mix eggs with sugar. Add the melted mix, then flour and vanilla. Cut the Milka bar and fold it in. Bake in a round tray at 180C for 25-30 minutes. You'll end up with a decadent brownie cake filled with chocolate and toffee.