Preheat oven to 350 degrees F (175 C).

To make the crust, add the Oreos to a food processor or blender and grind into fine crumbs. You do not need to remove the filling from the Oreos.

Add the Oreo crumbs to a bowl and combine with the melted butter.

Pour the mixture into your pie pan (a 9-inch pie plate works well) and press into an even layer on the bottom and up the sides. Be sure that the crust goes all the way up the sides so that your ice cream isn’t touching the pie plate, which will make slicing and serving easier later.

Bake the crust at 350 degrees F (175 C) for 8-10 minutes. Set aside to cool completely.

In a large mixer bowl, combine the softened cream cheese and granulated sugar. Mix until well combined and smooth, scraping down the sides of the bowl as needed.

Add the cocoa powder and mix until well combined and smooth.

Slowly add the milk, one tablespoon at a time, mixing until VERY well combined after each addition. Scrape down the sides and make sure the mixture is smooth and creamy before adding more to avoid lumps.

Add the 5 tablespoons of Baileys Irish Cream, two tablespoons at a time, and mix until well combined and smooth after each addition. This will again help avoid lumps in your filling.

Add the vanilla extract and mix until well combined. Set this mixture aside.

In another mixer bowl, add the 1.25 cups cold heavy whipping cream and 0.5 cup powdered sugar. Whip on high speed until stiff peaks form.

Gently fold the whipped cream into the cream cheese mixture in two parts until well combined.

Add half of the ice cream mixture to the cooled crust and spread into an even layer.

Add the mini marshmallows in an even layer on top of the first ice cream mixture.

Drop spoonfuls of the remaining ice cream mixture on top of the marshmallows and gently smooth into an even layer.

Freeze the pie until firm, approximately 5-6 hours, or overnight.

To make the whipped cream topping, add the 0.75 cup cold heavy whipping cream, 0.5 cup powdered sugar, and 2 tablespoons Baileys Irish Cream to a large mixer bowl. Whip on high speed until stiff peaks form.

Pipe or spread the whipped cream onto the top of the frozen pie and garnish with sprinkles, if desired. Store the pie well covered in the freezer until ready to serve.