Prepare ahead

The gelatins can be refrigerated for up to 2 days.

1. Sprinkle the gelatin over ½ cup water in a small bowl. Let stand about 5 minutes, or until the mixture is spongy. Place the bowl in a small frying pan of simmering water. Stir the gelatin mixture constantly until melted. Remove from the frying pan.

2. Stir 2 cups tepid water, the liqueur, and the dissolved gelatin together in a large measuring cup until combined. Divide among four 8oz (240ml) dessert glasses. Refrigerate at least 3 hours, until set. Top each with a dollop of whipped cream and some grapes, and serve chilled.