Cut the watermelon in half and use a melon baller to scoop out the flesh, then place in a shallow container with a lid.
Strain out excess liquid from container. Slowly add the bourbon and fennel-infused Cocchi Americano into the container, allowing the liquid to be absorbed before adding more. (The liquid should eventually be completely soaked up by the melon.) Put a lid on the container and freeze for 3 to 4 hours. Scoop out into coupe or bowl. Garnish with sea salt, black pepper and chopped basil.
*Fennel-infused Cocchi Americano: Add 1/2 cup chopped fennel fronds and a 750 mL bottle of Cocchi Americano to a jar. Seal and refrigerate for 24 hours, then strain out solids. Store in the refrigerator for up to several weeks.