1. To prepare cream: Stir together water and gelatin in a small heatproof cup or bowl. Microwave, uncovered, on High until the gelatin has completely dissolved but the liquid is not boiling, 20 to 30 seconds. (Alternatively, bring 1/2 inch water to a gentle simmer in a small skillet. Set the bowl with the gelatin mixture in the simmering water until the gelatin has dissolved completely.) Stir the mixture until smooth.
2. Place strawberries, sugar and vanilla in a food processor and puree. Add sour cream; pulse to combine. With the motor running, slowly add the dissolved gelatin. Pour the cream into four 8-ounce bowls or wineglasses. Cover and refrigerate until set, about 3 hours.
3. To prepare topping and serve: Toss diced strawberries and sugar in a small bowl; let stand until slightly juicy, about 2 minutes. Divide among the creams.

Yield: 4 servings