Spray a 9-inch springform pan with nonstick spray for easy removal. In a food processor, pulse the Oreo cookies into fine crumbs, then transfer to a bowl. Mix in the melted butter until fully combined. Firmly press the crumb mixture into the bottom of the pan for an even layer. Freeze the crust for 30 minutes to set before adding the filling.

In a medium saucepan, heat the heavy cream and Baileys over medium heat until the mixture is simmering, stirring occasionally to prevent burning. Remove from heat and pour it over the chopped 60% cocoa chocolate bars in a large bowl. Let it sit for a few minutes, then whisk until smooth and shiny. Incorporate the room temperature unsalted butter, stirring until melted and the mixture is velvety.

In a separate mixing bowl, beat the cold heavy cream and confectioners' sugar using an electric mixer on medium speed until medium-soft peaks form. This should take about 3-5 minutes. Make sure not to over-whip.

Carefully pour the smooth chocolate filling into the chilled Oreo crust, spreading it evenly with a spatula. Tap the pan lightly on the counter to eliminate any air bubbles. Cover the pie with plastic wrap and refrigerate for at least 3 hours, or ideally overnight, to ensure it fully sets and develops that luxurious, creamy texture.

Once the pie is set, remove it from the refrigerator. Dollop the freshly whipped cream on top, gently swirling it to cover the filling while leaving the edges visible. For an elegant touch, sprinkle chocolate shavings on top before slicing.