In a small saucepan over medium heat, combine the blackberries, and lemon juice and zest, if using (or substitute fruit of choice, amount directed below).
As the mixture begins to boil, mash the fruit with the back of a fork until it breaks down. This should take 5 minutes, give or take a few minutes depending on the type of fruit used.
Remove the pan from the heat. Stir in the honey, starting with 1 to 2 tablespoons. Taste, and add more honey to your liking.
Add the chia seeds and stir to incorporate. Let the jam set for about 5 minutes to thicken. Cool and transfer to a jar or air-tight container and refrigerate.
The jam will keep for approximately 2 weeks in the fridge and may be frozen. You can swap the blackberries for any fruit you like. We recommend to start with a berry base and then you can add any fruit you like. The total amount should equal 10-12oz.