Toss the strawberries in a food processor and pulse until almost smooth, leaving a bit of chunkiness for texture. If you don’t have a food processor, you can just coarsely chop the strawberries and then mash them with a potato masher.
In a medium saucepan, combine the strawberries, the blueberries and the honey, and bring to a simmer over medium-high heat. Make sure you’re stirring frequently.
When it starts simmering, reduce heat to medium-low and simmer for 5 minutes or so, mashing some of the blueberries with a fork or potato masher and leaving some of them whole for texture.
Stir in the chia seeds and cook for another 15 minutes or so, stirring frequently until the jam thickens to your liking.
When the jam is thick, remove the pan from the heat and stir in the vanilla.
Let it cool a bit, then transfer it into a jar with an airtight lid, where it will keep for up to a couple weeks in the fridge.