For the raspberry ice cream, place the defrosted raspberries into the bowl of a food processor with the caster sugar and blitz to a puree. Pass through a sieve into a bowl and set aside.
Drain the cashews and tip into the bowl of the processor (there’s no need to wash the bowl out). Add the coconut milk and blitz for 3–5 minutes to a smooth cream. Melt the coconut oil over a low heat and as soon as it starts to melt, remove from the heat and stir until melted. Try and keep the melting temperature as low as possible so the mixture is as cold as possible.
Add the raspberry puree to the food processor with melted coconut oil and blitz for 1–2 minutes until very smooth. Add the raspberry extract drop by drop to taste, blitzing well between each addition.
Pour the mixture into a shallow tray and freeze for 15 minutes to chill.
For the chocolate ganache, tip the chocolate chips into a small bowl. Pour the coconut milk into a small pan and heat until just starting to bubble around the edge. Remove from the heat, then pour over the chocolate chips. Leave to stand for 2 minutes, then stir to a smooth ganache. Add the sea salt and stir to mix.
Pour into the lined 10cm hemisphere mould and leave to cool, then chill to set. Once set, freeze for 30 minutes.
Spoon the chilled raspberry mixture into an ice cream machine and churn for 30–45 minutes to ice cream.
Spoon the ice cream into the large hemisphere mould, then push the smaller hemisphere mould (that is lined with clingfilm on the outside) into the ice cream until the rims of both moulds are level. Freeze for 1 hour 30 minutes until firm.
For the chocolate sponge, heat the oven to 180°C/160°C fan/350°F/Gas 4. Sieve the flour, bicarbonate of soda and salt into a bowl. Pour the milk into a pan and warm gently. Remove from the heat and add the coconut oil, cocoa powder, sugar and vinegar and stir to a smooth batter.
Pour the batter over the flour mixture and stir until smooth. Spoon into the lined sponge tin and bake for 15–20 minutes until well risen, and a skewer inserted into the centre comes out clean. Transfer to a wire rack and leave to cool in the tin.
For the Italian meringue, pour the aquafaba into the bowl of a stand mixer, fitted with the whisk attachment. Add the cream of tartar and whisk on medium speed to soft peaks.
Tip the sugar into a pan, add the vege-gel and 5 tbsp water. Melt the sugar very gently over a low heat. Once the sugar has completely dissolved, increase the heat to a rapid boil until the syrup reaches 121°C/250°F on a sugar thermometer.
Remove the pan from the heat. With the whisk at full speed, slowly pour the hot syrup onto the whisked aquafaba in a thin stream. Continue whisking until the meringue is very thick and glossy and has cooled to room temperature. Spoon two-thirds of the meringue into a piping bag fitted with a large closed star nozzle.
To assemble turn the sponge out onto a serving plate, then turn out the chocolate hemisphere. Turn out the raspberry ice cream and place the chocolate hemisphere into the centre of the raspberry hemisphere. Invert onto the sponge.
Spread the remaining meringue over the dome of ice cream to seal and coat the ice cream and sponge, then pipe decorative swirls of meringue all over the top.
Using a blowtorch, gently brown the meringue before serving immediately.