In a mixing bowl, combine the crushed digestive biscuits and melted butter until well mixed. Press the mixture firmly into the bottom and up the sides of the tart pan. Chill in the refrigerator for 15 minutes.
In another bowl, combine the softened cream cheese, heavy cream, powdered sugar, ground cardamom, lemon zest, and orange zest. Whisk until smooth and creamy.
Pour the cream cheese mixture into the chilled biscuit crust, spreading it evenly with a rubber spatula.
Arrange the assorted fresh fruits over the cream cheese filling, creating a colorful pattern.
Cover the tart with plastic wrap and refrigerate for at least 2 hours to set.
Once set, remove from the refrigerator, garnish with fresh mint leaves and additional citrus zest if desired. Slice into neat pieces and serve.
