How to Make It
Line a 9-inch square baking pan with plastic wrap. Pour the coffee into a medium saucepan and sprinkle the gelatin over it. Let stand until softened, about 5 minutes. Heat the coffee over moderate heat, whisking, until the gelatin dissolves, about 1 minute. Add 1 pint of the ice cream and cook, whisking, until hot, 3 to 5 minutes.
In a large bowl, combine the coffee mixture with the remaining pint of vanilla bean ice cream and whisk until smooth, then whisk in the whiskey and a generous pinch of salt. Pour the panna cotta batter into the prepared pan and refrigerate until set, at least 3 hours.
Invert the panna cotta onto a carving board and, using a 2-inch round biscuit cutter, cut into rounds and serve with caramel sauce.