1/2 bunch fresh mint, leaves removed from stems, rinsed well (about 1/2 cup)
1/2 cup white grape juice
1 tablespoon freshly squeezed lime juice
1 1/2 teaspoons unflavored gelatin (1/2 envelope)
1 six-ounce container fresh raspberries, rinsed
1/2 cup heavy cream
1 tablespoon confectioners' sugar
Place a medium saucepan over high heat. Add sugar, the water, and mint, and bring to a boil. Reduce heat to medium; simmer 2 minutes, swirling pan to dissolve sugar. Strain mixture through a fine mesh sieve into a small bowl; discard mint.
Combine grape juice, lime juice, and gelatin in a medium heatproof bowl set over a pan of simmering water, and stir until gelatin is dissolved. Remove bowl from heat; add mint syrup and berries, stirring with a wooden spoon to break some berries into pieces. Divide mixture among four 6-ounce ramekins. Cover with plastic; refrigerate until firm, at least 4 hours and up to 2 days.
Just before serving, place heavy cream in the bowl of an electric mixer fitted with the whisk attachment; beat on medium speed until soft peaks form, 3 to 4 minutes. Add confectioners' sugar, and continue beating until soft peaks return, 1 to 2 minutes. To serve, spoon a dollop of whipped cream onto each serving.