Blitz 4 peeled and stoned peaches with the juice of 1 lemon until smooth. Can be made up to 1 day in advance and kept in the fridge.
In the same processor (there’s no need to wash it) blitz 200g/8oz raspberries with 3 tbsp golden caster sugar and the juice of ½ lemon. Pass the raspberries through a sieve to get rid of any pips. The purée will keep in the fridge for 2 days in an airtight container.
On the day, carefully pour a layer of raspberry purée, then a layer of peach purée, into Champagne flutes and top up with Champagne or a good-quality sparkling wine.