Preheat oven to 180°C/160°C fan. Grease and line base and side of a 20cm round cake pan.
To make the brownie base, stir butter and chocolate in a large saucepan over very low heat until just melted. Remove from heat and cool slightly. Stir in sugars, then flour, egg and sour cream; mix well.
Pour mixture into prepared pan; bake for 35 minutes. Cool in pan.
Meanwhile, make choc mint ice-cream.
Using a 2-litre pudding bowl as a guide, trim brownie to fit inside top of the bowl.
Fold the nougat into the partially set ice-cream and spoon into pudding bowl; smooth the top. Place the trimmed brownie on top of ice-cream; cover with plastic wrap and freeze overnight or until firm.
To unmould, dip the pudding bowl into hot water for a couple of seconds, run a palette knife around the side, invert onto a chilled serving plate and then freeze
until required. Serve topped with Ice Magic, red currants and raspberries.
Choc mint ice-cream
Place the chocolate, brandy and half the cream in a large heatproof bowl over a large saucepan of simmering water; stir occasionally until smooth. Set aside and keep warm.
Whip remaining cream to soft peaks and set aside. In a separate small pan, stir the sugar, glucose and 80ml water over medium heat until sugar dissolves. Bring to the boil and cook syrup for 3 minutes or until syrup reaches 118°C on a sugar thermometer.
Whisk the yolks in a large bowl with an electric mixer for 2-3 minutes or until pale and creamy. Whisking continuously, gradually add hot sugar syrup, then beat for 2-3 minutes or until cooled to room temperature. Fold in the chocolate mixture, then the whipped cream and peppermint essence.
Freeze for 30 minutes or until slightly firmer and starting to set. (This will prevent the nougat from sinking to the base of the mixture.)