Add the milk to a mason jar or a container with a lid. Add the chia seeds and vanilla extract, secure the lid and shake straight away so the chia seeds don't clump together. Add the mashed berries and shake again.
Give it a few more shakes over the next 15 minutes, so the mixture thickens evenly. Leave in the fridge for a few hours or make the night before.
Serve with extra berries
Notes
I also love the combination of coconut and mango - use whatever fruit is in season Sweeten with maple syrup or honey from 12 months old