1. In a small saucepan, combine the raspberries and sugar. Cook over low heat, covered, stirring occasionally, until the berries are soft and the sugar dissolved, 5 to 10 minutes. Strain into a medium bowl, pressing the berries to get all the juice. Stir in the pepper. Chill until completely cold, about 20 minutes. Stir in the Grand Marnier.
2. In a large bowl, beat the cream just until it holds firm peaks when the beaters are lifted. Fold in the raspberry mixture and the halved strawberries until just combined. Serve in stemmed glasses or bowls, topped with the reserved whole strawberries.