01 - Place mixed berries in a medium saucepan over medium heat. Cook, stirring occasionally, until berries begin to break down and release their natural juices, approximately 5 minutes.
02 - Use a fork or potato masher to mash the cooked berries until reaching your preferred texture, whether chunky or completely smooth.
03 - Stir in maple syrup (or honey), chia seeds, vanilla extract, and lemon juice until thoroughly combined.
04 - Remove saucepan from heat. Let mixture stand for at least 5 minutes, stirring occasionally to distribute chia seeds as they absorb liquid and thicken the jam.
05 - Taste the jam and add additional sweetener if needed to achieve desired sweetness level.
06 - Transfer jam to a clean glass jar. Allow to cool completely at room temperature before sealing with lid and refrigerating.