01 - Place the berries in a medium saucepan over medium heat. Cook, stirring occasionally, until the berries begin to break down and release their juices, about 5 minutes.
02 - Use a fork or potato masher to mash the berries to your preferred texture, whether chunky or smooth.
03 - Stir in the maple syrup (or honey), chia seeds, vanilla extract, and lemon juice if using.
04 - Remove from heat and let the mixture sit for at least 5 minutes, stirring occasionally. The jam will thicken as the chia seeds absorb the liquid.
05 - Taste the jam and add more sweetener if desired.
06 - Transfer the jam to a clean jar. Allow to cool completely before sealing and refrigerating.
07 - Store in the refrigerator for up to 1 week.