Leave the yoghurt to drain through a cloth into a bowl for 12 hours, add the pulp of the vanilla and flavour with icing sugar. Beat the parfait in a planet mixer until light and airy and add the raspberry purée. Transfer to a piping bag and pipe the mixture into a savarin mould. Store in the freezer.
For the lemonade, heat the lychee purée with the sugar and the raspberry purée. Add the sprigs of mint and leave to infuse briefly. Pass through a fine sieve and pour into a siphon. Aerate with a carbon dioxide cartridge and store in the refrigerator.
Reduce the raspberry purée with the sugar water to the desired thickness and store in a siphon.