Wash and hull the strawberries. Chop them into smaller pieces and puree them in a blender or food processor until smooth.

Pour the strawberry puree into a medium saucepan. Add the water (or strawberry juice), chia seeds, sweetener (if using), lemon juice, and vanilla extract (if using). Whisk everything together thoroughly.

Place the saucepan over medium heat and bring the mixture to a simmer, stirring constantly.

Once it starts simmering, reduce the heat to low and continue to stir for about 5-7 minutes, or until the chia seeds have started to absorb the liquid and the mixture has thickened slightly. It should resemble a loose jam.

Line an 8x8 inch baking dish with parchment paper (if using).

Pour the strawberry chia seed mixture into the prepared dish, spreading it out evenly.

Cover the dish with plastic wrap or a lid and refrigerate for at least 4 hours, or preferably overnight, to allow the chia seeds to fully absorb the liquid and set.

Once the jelly has set, remove it from the refrigerator. If you lined the dish with parchment paper, lift the edges of the paper to remove the entire block of jelly.

Place it on a cutting board and use a sharp knife to cut it into squares.

Serve immediately and enjoy!