Heat the berries in a pan over medium heat till the juices release from the fruit and go nice and bubbly, and the larger fruits like cherries or blackberries are breakable with a spatula
Allow to cool then add all the berries and juice to the blender and blend till smooth
Add to a container or glass jar then add the chia seeds and stir in to combine.
Pop in the fridge to set. This will thicken as it cools
Store in the fridge and use within 5 days.