- 250g caster sugar
- 400g blackberries
- Juice of ½ lemon
- Put the sugar in a pan with 250ml water and bring to a simmer, stirring occasionally, until all the sugar has dissolved. Set aside to cool completely.
- Put the blackberries and lemon juice in a small food processor or blender and whizz to a purée (or whizz with a stick blender in a jug), then push through a fine sieve into a mixing bowl using the back of a spoon (discard the seeds). Add the cooled syrup and mix until combined. Churn in an ice cream machine until smooth; freeze overnight until solid.