Begin by crushing the Oreo cookies into fine crumbs using a food processor or a ziplock bag and a rolling pin. In a mixing bowl, combine the cookie crumbs with melted unsalted butter until well blended. Press this mixture firmly into the bottom of a 9-inch springform pan using the back of a measuring cup to form an even layer.

In a large mixing bowl, beat softened cream cheese with granulated sugar and espresso powder until the mixture is smooth and creamy, about 2-3 minutes. Gradually fold in the whipped heavy cream until fully incorporated.

Pour the espresso cheesecake filling over the prepared crust in your springform pan. Use a spatula to spread the filling evenly and smooth the top.

Cover the springform pan with plastic wrap and refrigerate for at least 5 hours, or preferably overnight, until the cheesecake is firm and set.

While the cheesecake is chilling, make the chocolate ganache by heating heavy cream in a small saucepan over medium heat until it just begins to boil. Pour the hot cream over chopped chocolate and stir until smooth.

Once the cheesecake is set, carefully pour the cooled ganache over the top, spreading it evenly with a spatula. Return the cheesecake to the fridge for an additional 30 minutes to let the ganache firm up.

Run a knife around the edges of the springform pan before releasing the sides. Slice the cheesecake and serve, optionally with whipped cream and crushed espresso beans.