In a small pan, create a simple syrup by bringing water, mint and sugar just to a boil while stirring to dissolve sugar. Simmer for 1 minute. Remove from heat and set aside to cool then strain to discard mint before use.
½ cup water
½ cup fresh mint
½ cup sugar
Place watermelon cubes in stand blender or food processor and puree. Pour through a sieve or tightly woven strainer into a large bowl. If using a hand strainer, take the back of a spoon to push through as much melon as you can into bowl. Discard any seeds and remaining pulp. Continue until all watermelon has been pureed and strained.
4 cups seedless watermelon
Add cooled sugar and lemon juice to watermelon puree, then pour mixture into an 8 inch by 8 inch glass dish. Freeze for several hours or until completely frozen.
1 tablespoon fresh lemon juice
Break up with a knife into frozen pieces and place back in the blender or use a hand blender should work, too. Place pureed sorbet into a freezer-friendly container and return to your freezer for a couple of hours. Enjoy!