You can use any type of container to make these but it’s easier to do with the plastic popsicle molds. You will need to purchase popsicle sticks or something similar either way.
Cut a watermelon in half, then scoop out 3 1/2 C. flesh with a large spoon and place in a blender or water-tight food processor. You can remove the seeds or leave them (if applicable) for a nice visual touch.
Add 2 T. sugar and 1 T. lemon or lime juice and puree the mixture until smooth but still slightly grainy. If you’re looking to make them even more flavorful, add a teaspoon of zest (lemon or lime) or grated ginger.
Skim off the foam and then pour the mixture into the molds or containers, filling them 2/3 of the way. If you’re not using molds with tops, you will need to wait an hour or so before inserting the popsicle sticks.
In a separate container, mix together 1 1/2 T. sugar with half of a 12 oz. can of coconut milk. Stir until the sugar dissolves, then refrigerate.
After at least three hours, use the coconut mixture to top off all the popsicles.
Freeze for another 3 hours, or until the popsicles are completely frozen.
To remove popsicles, dunk the molds in a bowl of water water — without getting the stick-sides wet — and use the sticks to pull them out.
Popsicles will store for a few days in their molds or containers but if you want to keep them longer than that it’s best to remove them and store in plastic bag, separated by wax paper.