Prepare a 9-inch deep-dish pie plate or springform pan by greasing it with butter or nonstick spray.

In a food processor, pulse the Oreo cookies until fine crumbs. Mix with melted butter and sea salt until resembling wet sand.

Press the crumb mixture into the prepared pan evenly and place in the freezer for 15-20 minutes.

Heat the hot fudge topping in a small saucepan over low heat until pourable. Stir in heavy cream if necessary.

Remove the crust from the freezer and pour the warm fudge over the crust, spreading it evenly.

Let the fudge set in the freezer for another 15 minutes before adding the ice cream layer.

Soften coffee ice cream at room temperature for 10-15 minutes, mix in espresso powder if desired.

Spoon coffee ice cream over the fudge layer and smooth the top with a spatula.

Cover with plastic wrap and freeze for at least 4 hours.

Whip together heavy whipping cream, powdered sugar, cocoa powder, vanilla extract in a mixing bowl until medium-stiff peaks form.

Spread or pipe the whipped cream over the ice cream layer once the pie is frozen.

Freeze the Mud Pie for an additional 30-60 minutes before serving and let it sit at room temperature for 10-15 minutes before slicing.