Crush the Oreo cookies in a food processor until fine crumbs form. Melt the unsalted butter and mix it with the cookie crumbs until well combined. Press the mixture into a mini cheesecake pan or springform pan to form an even layer.

Heat heavy cream in a saucepan over medium heat until hot and steamy. Pour it over chopped semi-sweet chocolate in a bowl and let it sit for a minute. Whisk until smooth to create ganache.

Pour the ganache over the prepared Oreo base and spread evenly. Cover with plastic wrap and refrigerate for at least 1 hour for mini desserts or 6-8 hours for a larger cake.

Once set, remove the dessert from the pan and slice into pieces or scoop out servings. Top with whipped cream made by whisking heavy cream with powdered sugar and vanilla extract.