Stir together vanilla wafer crumbs, powdered sugar, cocoa and melted butter.
Line the bottom of a springform pan with a circle of parchment paper. Press the wafer crumbs firmly into the bottom of the pan. Set aside.
To prepare cheesecake:
Melt chocolate in microwave in 30 second increments. Stir and return to microwave for another 30 seconds. When most of the chocolate has melted just continue to stir until smooth. Do not heat too much in microwave or it will scorch and dry out.
In large mixing bowl, beat cream cheese until light and fluffy.
Gradually add in condensed milk until incorporated.
Add melted chocolate, eggs, liqueur and vanilla and mix well.
Pour into chocolate crust.
Bake 65 minutes or until center is set.
Remove to wire rack, run knife around pan to loosen cake from edges, then let cheesecake cool completely.
Remove sides of pan and refrigerate.
Garnish cheesecake with fresh fruit and mint leaves. When serving, add a dollop of whipped cream to each slice and top with slice of fruit.