- 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.
- 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.
- To prepare topping & serve: Toss diced strawberries and sugar in a small bowl; let stand until slightly juicy, about 2 minutes. Divide among the creams.