Combine ricotta cheese, confectioners' sugar, sour cream and coffee liqueur in a large mixing bowl; mix well.
Set aside. In the container of an electric blender or food processor, process cookies, in small batches, until finely crushed.
Remove 6 cherries from cherry filling; reserve for garnish. To assemble dessert, spoon 2 tablespoons ricotta cheese mixture into six 8-ounce parfait glasses.
Add 2 tablespoons cookie crumbs to each glass; top each with 2 tablespoons cherry filling. Repeat ricotta, crumb and cherry layers. Finish each serving with an equal portion of the remaining ricotta cheese mixture.
Garnish with reserved cherries, grated chocolate and mint leaves, if desired. Let chill 2 to 3 hours before servings.