Step 1

Blend: Scoop the fruit out of the watermelon. In a blender or food processor, puree watermelon until it reaches a thin, even consistency. You should have about 6 cups of watermelon juice. If you have seeds in your watermelon, strain them out with a mesh colander. Stir in lime juice and sugar.

Step 2

Freeze: Pour into a large baking dish and freeze for about 2 hours. Remove and scrape at frozen sides and top. Place back in freezer. Repeat this process of freezing and scraping, every few hours, until mixture is completely frozen and scraped.