Select the berries, rinse with cold water and drain. Puree 100 g berries with the cutting stick of the hand mixer. Mix the puree and juice. Add sugar, lemon peel and carved vanilla pod and heat up. Simmer for 5 minutes.
Remove lemon peel and vanilla pod. Stir the starch with some cold water until smooth. Bring fruit juice to the boil, stir in the mixed starch. Let it cool down while stirring. Fold in berries and serve