They use a pour over coffee method, pouring the whiskey and water over the coffee right at the bar.
Place sugar cube in an Irish coffee mug. Add coffee and whiskey and stir to combine. Top with whipped cream and bitters, if using.
1 small sugar cube
6 ounces hot freshly brewed coffee
2 ounces GrandTen Distilling South Boston Irish whiskey
Whipped cream (for serving)
A few dashes A few dashes Bittermens Xocolatl Mole Bitters (optional; for serving)