Method

• 1.
  Whisk together the egg yolks and sugar until light.
• 2.
  Place 600ml of the cream in a saucepan over medium heat until at scalding point. Add to the egg yolk mixture, beating to combine.
• 3.
  Melt chocolate in a heatproof bowl over a saucepan of simmering water (don't let the bowl touch the water). Cool slightly, then stir cream mixture into chocolate.
• 4.
  Add cocoa, place in a saucepan and cook over low heat until thickened. Cool a little, whisk in Nutella and syrup, then cool further. Whip remaining cream and fold into chocolate mixture.
• 5.
  Lightly grease a 25 x 11cm terrine and line with plastic wrap. Fill the terrine with the ice-cream and smooth the top. Freeze overnight or until firm. Remove from the freezer, dip the base of the terrine in a little warm water, then gently ease out onto a serving platter, discarding the plastic wrap. To serve, garnish with the extra cream and the chopped chocolates.