Method:

1. Pop the frozen berries, coconut sugar, lemon juice, mint and the vanilla bean into a small pot over a low heat and cook until the berries begin to collapse. You can use a spoon to crush the berries in the pot to help them along a little bit.
2. Once broken down remove the vanilla pod and set aside
3. Pour the remaining contents through a sieve into a bowl pushing as much as possible through the sieve with the spoon, use a small knife to scrape out the vanilla pod and add to the puree berry mixture.

During Winter most berries are super expensive and this can be a great time to use frozen berries which are not necessarily a lesser ingredient than fresh.