Chill the ice cream bowl for at least 24 hours or until solid. You should not hear any water sloshing around when you shake the bowl.
In a saucepan over medium heat, combine the heavy cream, whole milk, granulated sugar, cocoa powder, instant espresso powder, and salt. Whisk until combined.
Heat until the cocoa powder has dissolved and the mixture is just simmering.
Add the chopped chocolate to the saucepan. Stir until completely melted.
Pour the mixture into a large bowl.
Stir in the vanilla extract.
Press plastic wrap to the surface of the mixture. Chill in the refrigerator for 3 hours, or until cold.
Churn the ice cream mixture in the bowl of your ice cream machine according to your manufacturer’s instructions (mine took about 20 minutes), until it is thick and the consistency of soft-serve ice cream.
In the last two minutes, add all but two tablespoons of the chopped chocolate sandwich cookies and churn until they are evenly distributed. Reserve remaining cookies.
Spoon half of the ice cream into a shallow container or a loaf pan. Add half of the chocolate fudge sauce and lightly swirl with a spoon.
Repeat with remaining ice cream and fudge sauce. Top with remaining chopped cookies.
Press plastic wrap or wax paper to the surface of the ice cream. Freeze for at least 4 hours, or until solid. Let sit at room temperature for about 5 minutes before serving.