Lightly oil a 1litre glass pudding basin or bombe mould if you have one. Line with cling film and then line the vanilla ice cream over the whole of the inside of the bowl or mould in a 1cm layer leaving a good hollow in the middle. Freeze for 10-15 minutes and then smooth again to make an even layer. Freeze until firm – approx. 2 hours. Meanwhile, make the bombe mixture. Heat the sugar and water together in a small saucepan until the sugar has dissolved. Bring to the boil and then simmer until the mixture reaches the soft ball stage (115°C) on a sugar thermometer. Meanwhile, beat the egg yolks until they are just mixed, gradually pour in the hot syrup beating constantly for at least 5 minutes on a high speed. Turn the electric whisk to a lower setting and beat for another 5 minutes until the mixture is cool and it forms a thick mousse.
Fold in the melted chocolate and toasted chopped hazelnuts and finally fold in the cream. Spoon this mixture into the hollow in the middle of the ice cream and smooth the surface flat with a spatula. Place the lid on top or cover with cling film and freeze until solid – at least 8 hours. When ready to serve, make the chocolate sauce. Place the chocolate, butter and honey into a bowl that fits snugly over a pan of simmering water and leave to melt stirring occasionally. Whisk in the cream until smooth. To turn out the bombe, remove from the freezer about 10 minutes before you need it, invert the bombe onto a serving plate and remove the cling film.
Decorate with chocolate curls and then cut into wedges to serve. Serve with the hot chocolate sauce over the top – if you like.
See more Dessert recipes