Fresh raspberry and lemon fizz

Method

1. Blitz the raspberries and caster sugar together in a food processor until smooth, then pour through a sieve set over a bowl and press, to remove the seeds.
2. Mix the raspberry purée with the lemon zest and juice and chill until needed. Just before serving, slowly mix the purée with the chilled fizzy water, stir in some ice cubes and whole fresh raspberries, and serve.