Mint chocolate ice cream parfait bombes

Method

1. Put the cream and chopped mint in a heavy-based saucepan and heat gently until just boiling. Transfer to a blender, then whizz until smooth and bright green. Put a sieve over the pan and strain the mixture back into the pan (discard the solids in the sieve). Return to a low heat and keep warm.
2. Put the egg yolks in a large heatproof mixing bowl, then whisk in 50g caster sugar and the cornflour. Pour the warm cream slowly over the yolk mixture, whisking constantly, then strain through a sieve back into the cleaned pan. Return to the heat and stir until thickened, then strain once more into a clean heatproof bowl. Leave the custard to cool with a sheet of cling film touching the surface to prevent a skin forming, then chill.
3. Once the custard has chilled, taste and add 5-10 drops of mint extract (see tips). In a large clean bowl, using an electric hand mixer, whisk the egg whites until stiff peaks form when the beaters are removed. Whisk in the remaining 150g sugar a tablespoon at a time until the mixture is smooth and glossy. Stir a large spoonful of the whisked egg white into the custard mixture to loosen it then, using a large metal spoon, quickly fold in the rest using a figure-of-eight motion. Drizzle about 100ml of the chocolate sauce over the mixture and fold in quickly for a marbled effect.
4. Divide half the ice cream mixture equally among the moulds, dot another 1 tsp chocolate sauce in the middle of each, then fill with the remaining mixture. Cover each mould with a few layers of cling film and freeze for 6 hours or until solid.
5. Once frozen solid, remove the dariole moulds from the freezer, boil the kettle and pour some of the water into a small heatproof bowl. Dip the base of each mould in the hot water for 2-3 seconds, then turn over and put on a plate. Tap firmly on the bottom to release the bombe. Run a dinner knife around the edge of the parfait if you’re having difficulty turning them out. Working quickly, put all the bombes on a wire rack set over a sheet of baking paper.
6. Carefully pour the melted chocolate over the top of each bombe to completely coat in a thin layer, then return to the freezer for at least 1-2 hours until set, or until ready to serve (see make ahead).