Crush Oreo cookies finely.
Mix melted butter with crushed cookies and press into the tart pan.
Bake in a 180°C oven for 10 minutes and let cool.
Whip heavy cream with sugar.
Melt dark chocolate using a double boiler.
Mix whipped cream into the melted chocolate to make chocolate cream.
Spread the chocolate cream evenly over the cooled tart base.
Chill in the refrigerator for at least 2 hours until set.