Pour coconut milk, coconut water, and granulated sugar into a medium saucepan and set it over medium heat. Stir continuously until the sugar dissolves completely—you'll know it's ready when you run a spoon across the bottom and no granules remain. The why here matters: heating helps the sugar integrate smoothly instead of settling into gritty pockets that ruin the texture of your coconut lime popsicles cozy.

Remove the pan from heat and stir in the sweetened condensed coconut milk and lime juice until the mixture looks uniform throughout. This step takes exactly two minutes of stirring, and I've learned the hard way that rushing here means uneven flavor distribution in your finished pops. The acid from the lime juice will thicken the mixture slightly—that's exactly what should happen.

In a small bowl, whisk together the agar-agar powder with the cornstarch and 1/4 cup water until absolutely no lumps remain. Pour this mixture into the saucepan and whisk vigorously for one full minute to break up any clumps. The agar-agar is what transforms these coconut lime popsicles cozy from melting disappointments into bars that hold their shape, so this step isn't optional.

Return the saucepan to medium heat and let it simmer for exactly 3 to 4 minutes while stirring constantly. You'll notice the mixture begins to thicken and coat the back of a spoon—don't skip this timing because it allows the agar-agar to activate properly. I confess I once pulled mine off early thinking I was being efficient, and the result was popsicles that stayed soft instead of freezing firm.

Stir in the lime zest and sea salt, then remove from heat and let the mixture cool to room temperature for about 15 minutes. Resist the urge to pour it into molds while it's hot—this ruins the set and creates an uneven texture throughout. The reason we cool it first is that warm liquid won't freeze consistently with the stabilizers we've added.

Pour the cooled mixture into popsicle molds, filling each one to about 1/2 inch from the top to leave room for expansion. Insert sticks and freeze for at least 8 hours, preferably overnight. I always make my coconut lime popsicles cozy in the evening so they're ready by the next day when the cravings hit.

To remove the popsicles, run warm water over the outside of each mold for 10 to 15 seconds until they slide out cleanly. Serve immediately or transfer to a freezer bag for storage up to three weeks.