Start by cutting a ripe watermelon into chunks. Using a blender, puree the watermelon until smooth. Then, strain it through a fine mesh sieve or cheesecloth to extract 4 cups of fresh watermelon juice.

In a saucepan over medium heat, gently combine your watermelon juice, honey or maple syrup, lemon juice, and gelatin. Whisk until the gelatin has fully dissolved. Do not let it boil.

Remove the saucepan from the heat. Pour the mixture into jelly molds or a baking tray.

Allow the jelly mixture to cool to room temperature before transferring it to the refrigerator. Let it sit for at least 4-6 hours, or until the jellies are firm.

Once set, gently remove the jellies from their molds or cut into squares if using a tray.