Add two cups of berries to a small saucepan on medium heat. Stir occasionally until the fruit is soft enough to mash with your spatula.
Turn off the heat and mash with a potato masher or fork to desired consistency.
Add the remaining ingredients and stir until blended. The mix will be runny but will thicken as it cools and the chia seeds begin absorbing the moisture.
Once cooled, spoon into an air-tight container and store in the fridge.