- 8 ounces watermelon (about 1/2 small), peeled and cut into cubes (1 1/2 cups)
- 3 tablespoons fresh lemon juice (from 2 lemons)
- Coarse salt and freshly ground pepper
- 12 fresh oysters, preferably Blue Point, scrubbed well
- Crushed ice cubes
- Garnish: thin strips lemon zest
- Puree watermelon in a blender until smooth. Strain mixture through a fine sieve into a 5-by-9-inch nonreactive loaf pan; discard solids. Stir in lemon juice, 1/8 teaspoon salt, and 1/2 teaspoon pepper. Cover with plastic wrap; freeze until firm, about 3 hours.
- Scrape granita with a fork until fluffy. Freeze again while shucking oysters.
- Shuck oysters, and arrange on a bed of crushed ice. Garnish ice with lemon zest. Top each oyster with 1 to 2 teaspoons granita toward the narrow end of the oyster shell.
Make Ahead: Granita can be frozen for up to 1 week. Rescrape before using.