Method

• 1.
  Grease a 22cm springform cake pan and line the base and sides with baking paper.

• 2.
  Crumble brownie into the bottom of the pan and press to form a firm base. If needed, add a little butter to bring the base together. Refrigerate until needed.
• 3.
  Place cream and sugar in a saucepan over medium heat and stir to dissolve the sugar.
• 4.
  Meanwhile, soak gelatine in cold water for 5 minutes to soften.
• 5.
  Place chocolate in a food processor and whiz until finely chopped. Add the hot cream mixture and whiz until melted and smooth. Squeeze water from the gelatine, then add the eggwhites and gelatine, and whiz to combine. Add cream cheese and Frangelico, if using. Whiz until very smooth. Pour mixture over base and refrigerate for 4 hours or until firmly set.
• 6.
  When ready to serve, make the icing. Place butter and icing sugar in the bowl of a stand mixer fitted with the paddle attachment. Beat until thick and pale. Beat in cocoa until combined. Gently fold in sour cream.
• 7.
  Remove cake from pan and place on a serving plate. Using a palette knife, spread icing over and decorate with hazelnuts and Ferrero Rocher chocolates.