Set aside 6 beautiful berries for garnish and slice remaining berries. In a mixing bowl toss strawberries with sugar and Grand Marnier. Set aside to macerate at least 15 minutes, and up to 1 hour for sugar to dissolve. Meanwhile, whip cream to soft peaks. Split biscuits, mound strawberries on bottom half, top with a dollop of whipped cream and replace biscuit top. Garnish with mint sprigs. Dip reserved berries into chocolate, and use to garnish plate.