Divide and arrange 3/4 cup of halved grapes in each of six dessert dishes. Sprinkle each with brown sugar and top with 1/3 cup sour cream. Chill until ready to serve.
A slightly fancier version of this is sometimes called Grapes Romanov. Arrange halved grapes in individual heatproof serving dishes, but top first with sour cream and then brown sugar. Chill for at least 1 hour so that the brown sugar melts into the sour cream, then caramelize or "brûlée" the sugar with a small torch or by placing the dishes under a preheated broiler until the sugar is bubbly, about 2 minutes. Serve immediately.
Calories 301; Protein 3 g; Carbohydrate 38 g; Fat 17 g; 48% Calories from Fat; Cholesterol 34 mg; Sodium 49 mg; Potassium 380 mg; Fiber 1.2 g.