In a food processor, crush the Oreo cookies into fine crumbs. Mix with melted butter until combined. Press this mixture into the bottom of a pie dish to form a crust. Freeze for about 15 minutes to set.

In a medium saucepan, heat the milk and sugar over medium heat until the sugar dissolves. In a bowl, whisk together the eggs, cocoa powder, and coffee. Slowly add the warm milk mixture to the egg mixture while whisking continuously. Return the mixture to the saucepan.

Cook the mixture over low heat, stirring constantly until it thickens (about 10-15 minutes). Remove from heat and stir in vanilla extract. Allow to cool completely.

Once the crust and custard have cooled, spread a layer of ice cream over the Oreo crust. Then pour the chocolate custard over the ice cream layer. Freeze for at least 3 hours until set.

Before serving, top with whipped cream and chocolate shavings if desired. Slice and enjoy this dreamy dessert!