Add the fruit to a sauce pan over medium heat and cook it until the fruit breaks down.
Mix in the chia seeds and lemon juice, then remove it from the heat and let it cool for about 5 minutes (this gives the chia time to do its magic and thicken the jam).
Add the fruit mixture to a blender or food processor and blend everything together. Then, give it a taste and sweeten it to your liking.
Serve immediately, or store it in an airtight container in the fridge for up to two weeks or the freezer for 3 months.