01 - Combine frozen watermelon cubes, coconut milk, lime juice, and agave syrup or honey in a high-speed blender.
02 - Blend on high speed until completely smooth and slushy, stopping to scrape down sides as needed.
03 - Taste the mixture and add additional agave or honey if more sweetness is desired.
04 - Pour into chilled glasses and garnish with lime slices and fresh mint leaves if using. Serve immediately.