Place a medium saucepan over medium-high heat to prepare for cooking.

Add the frozen strawberries to the pan and cover it with a lid to steam.

Cook until the berries are heated through, bubbling and starting to break down a bit, about 10 minutes, stirring occasionally.

Remove the pan from the heat and mash the berries with a fork or potato masher until almost smooth (it’s OK to have some small chunks remaining).

Stir in the chia seeds, lemon juice, and maple syrup until incorporated.

Transfer the berry mixture to a jar or other container with a tight fitting lid and allow to cool on the counter for at least 1 hour, uncovered. The jam will continue to thicken as it cools.

When jam reaches room temperature, stir it again, then cover and refrigerate for up to 1 week for best freshness.