A striking showcase for fresh strawberries, this make-ahead summer dessert is even more refreshing when topped with rosé granita (like frosé but better!).
Thinly slice 6 small berries; set aside 6 more for garnish. Coarsely chop the rest and puree in a food processor with sugar, salt, and lemon juice. Add 1 3/4 cups cold water; pulse to combine. Pass mixture through a fine-mesh sieve; discard seeds. Let mixture stand 10 minutes. Skim and discard any surface foam. (You should have about 4 cups purée.)
Sprinkle gelatin over 3 tablespoons cold water. Let stand 5 minutes. Heat 1/2 cup purée in a small saucepan over medium-high until warm to the touch. Add gelatin mixture, stirring until dissolved; then stir into 2 1/2 cups purée. Divide mixture among 6 heatproof glasses or shallow bowls. Add sliced strawberries, pushing them down into mixture. Refrigerate until set, at least 4 hours or, covered, up to 2 days.
In an 8-by-8-inch baking dish, mix together remaining 1 cup purée and rosé. Freeze 2 hours. Scrape with a fork. Freeze 1 hour and scrape again. Keep frozen; when ready to serve, scrape again.
Slice strawberries reserved for garnish; divide among glasses. Spoon 2 to 3 tablespoons granita on top. Serve immediately.