Line an 8X8 dish with foil. Add the chocolate to a large mixing bowl; set aside.
In a medium sized saucepan over medium heat, add the butter, sugar, cream, Irish cream liqueur, instant coffee granules and salt. Stir until the sugar and butter melt.
Continue to cook the fudge, stirring frequently, until it comes to a boil. Continually scrape sides of the pan to prevent mixture from sticking to them. Once boiling, insert a candy thermometer and cook until it reads 233 degrees Fahrenheit (114 C) on the thermometer. At this point, remove from heat.
Once the fudge reaches the desired temperature remove the saucepan from the heat and add to the mixing bowl with the chocolate; add the marshmallow cream. Stir until the chips and marshmallow cream are melted and well blended.
Add the vanilla and stir well. Pour the fudge into the prepared pan. Allow it to set at room temperature for 2 to 3 hours; place in refrigerator afterwards.