In the bowl of a large food processor fitted with an "S" blade, add in the frozen watermelon and lime juice. Process briefly to break down the watermelon; it should look like shaved ice in the bowl.

Add maple syrup to taste, starting with just 1 tablespoon, and process again. Taste the watermelon mixture and if you want it to be sweeter, add another tablespoon. Process again.

To help make the watermelon sorbet scoopable, you may need to add some water to help it blend into a smoother consistency. Start with 1 tablespoon of water, process, and then add another tablespoon (or more) if needed, until the watermelon sorbet looks smooth enough to serve.

This frozen dessert has a great texture right away, so I like to serve it while it's soft an scoop-able. If you want to make it in advance you can transfer this mixture to a pan and freeze it for 1 to 2 hours. If you freeze it longer than that, it will become very hard and difficult to scoop, so keep that in mind.

Leftover sorbet can be transferred into ice pop molds for an easy frozen dessert later, too.