01 - Place cubed watermelon in blender and blend until completely smooth. Strain through fine mesh sieve into large bowl to remove pulp if desired.
02 - Stir granulated sugar and lime juice into watermelon puree. Mix well until sugar is fully dissolved.
03 - In separate bowl, whip heavy cream with hand mixer until soft peaks form.
04 - Gently fold condensed milk, vanilla extract, and salt into whipped cream until incorporated.
05 - Pour watermelon puree into cream mixture and fold gently until well combined and uniform in color.
06 - Transfer mixture to loaf pan or airtight container. Cover tightly with plastic wrap or lid.
07 - Freeze for at least 4 hours or until firm enough to scoop.
08 - Let ice cream sit at room temperature for 5 minutes before scooping and serving.