Place the eggs, extra yolks, vanilla and sugar in a heatproof bowl. Place over a saucepan of simmering water and, using a hand-held electric mixer, beat for 6–8 minutes or until thick and pale. Remove from the heat and allow to cool slightly. Whisk the cream until stiff peaks form. Gently fold through the egg mixture until well combined. Fold through the chocolate and brownies. Pour into a 2 litre-capacity metal tin and freeze for 6 hours or overnight. Makes 2 litres.