Prepare the Crust: Crush chocolate biscuits into fine crumbs and mix with melted butter. Press the mixture firmly into a tart pan to form the base. Chill for 15 minutes.
Make the Mint Filling: Whisk together cream cheese, sugar, and mint extract until smooth. Pour over the chilled crust and level with a spatula.
Prepare Chocolate Ganache: Heat heavy cream and pour over chopped dark chocolate. Stir until smooth and pour over the mint layer.
Chill the Tart: Refrigerate for at least 2โ3 hours to set completely.
Serve: Garnish with shaved chocolate or thin mint leaves before serving for an elegant finish.