Place milk, 1 cup of cream, sugar, salt, and coffee beans in a medium sauce pan. Heat until the mixture is steaming, but not boiling. Remove from heat and cover for 1 hour to let the beans steep in the milk.
Once beans have steeped for 1 hour, place saucepan back over heat so it's steaming again. Remove from heat. Whisk egg yolks in a medium bowl until combined. Very slowly whisk in warm milk. Transfer mixture back to saucepan and set over medium heat. Stir constantly until mixture begins to thicken and is 170 degrees. Mixture should coat the back of the spatula. Remove from heat immediately so the mixture doesn't scramble.
Place remaining heavy cream in a large bowl and place strainer over bowl. Pour thickened yolk mixture through strainer to remove lumps and coffee beans. Stir with cream. Add Irish cream and whisk to cool the mixture down.
Chill mixture until completely cold, about 4-6 hours. Once chilled, ice cream base is ready for your machine. Freeze ice cream according to machine instructions. Make the espresso hot fudge by heating hot fudge in microwave for 15 seconds. Add espresso powder and mix together. Let it cool so it doesn't melt the ice cream.
Once mixture is ready, layer ice cream with Oreos and hot fudge. I did two layers to make sure every bite had tons to cookie and fudge. Freeze ice cream until solid, about 8 hours.