Add the Irish whiskey, cold brew coffee, and simple syrup to the glass. Stir until everything is well combined.For an extra smooth and creamy texture, you can shake the whiskey, cold brew coffee, and simple syrup together in a cocktail shaker with ice before pouring it over the ice in the glass.
Slowly pour the heavy cream over the top of the coffee and whiskey mixture.
If desired, top with a dollop of whipped cream and a sprinkle of cinnamon for garnish. Give the drink a final stir and enjoy!