Bring the blueberries and strawberries to a low boil on the stove top, stirring frequently. Reduce heat to low and simmer until the berries have softened, about 5 minutes. Mashed the berries to the desired consistency. We like ours with larger chunks.
Stir in the maple syrup and chia seeds. Cook the jam on low until it thickens, about 5-7 minutes. Stir the jam to keep it from sticking.
Remove the jam from heat and stir in the vanilla extract. Once jam has cooled to room temperature, pour it in a glass jar and store in the refrigerator.
Notes
The jam will keep in the fridge for up to 2 weeks, but you can also freeze it in an air-tight container.
You can substitute the maple syrup for honey or agave.